Showing papers in "Journal of Sports Medicine and Physical Fitness in 2017"

The efficacy of wearable activity tracking technology as part of a weight loss program: a systematic review.

Abstract: INTRODUCTION The world obesity rate has increased over the past two decades This problem has been linked to inactivity and lack of exercise among individuals which prompted the development of wearable activity tracking technology This technology is commonly offered as a bracelet, watch, or pendent that provides feedback of daily activity such as total step count, heart rate, and energy expenditure Despite the popularity of these devices, their efficacy to assist in behavior change and weight loss is still being studied The purpose of this systematic review was to appraise the current evidence on the efficacy of wearable activity devices when used in a comprehensive weigh loss program EVIDENCE ACQUISITION A systematic review was conducted according the PRISMA guidelines A search of electronic databases was conducted through December 2016 using the following keywords: activity monitor, consumer, wearable, technology, Fitbit®, Garmin®, Jawbone®, physical, activity, tracker, weight loss, walking, pedometer, accelerometer, step count, calories, obesity, digital, self-monitoring, and mobile health (mHealth) The grading of studies was conducted using the PEDro scale EVIDENCE SYNTHESIS We identified 7184 citations, 25 met the inclusion criteria Twenty-one studies scored a 6 or higher and four studies scored a 5 on the PEDro scale All subjects had a Body Mass Index (BMI) of ≥25 kg/m2 and were mostly women CONCLUSIONS The results suggests that short-term (<6 months) weight loss interventions using activity trackers may be a better option than a standard weight loss program in middle age or older adults Younger adults may not benefit from such technology

Does small-sided games training improve physical fitness and team-sport-specific skills? A systematic review and meta-analysis

Abstract: This paper aimed to systematically review and meta-analyse the training effects of small-sided games (SSG) on physical fitness and specific skills related to team sport according to the level of play and the period of the season. The search covered the following electronic databases (PubMed, Google Scholar, and ScienceDirect). The publications' search period ranged from 2000 to 2016. The terms (small- sided game, training, skill-based game, aerobic fitness, sprint, agility, jump and team sports) were used either singularly or combined in a systematic sequence. Appraisal of 16 articles (15 were meta-analysed) was performed after the application of exclusion criteria and quality assurance processes and the standardized mean effects were measured using random effects. The results revealed that SSG training had a large beneficial effect on maximal oxygen uptake VO2max (effect size 1.94; 95 % CL 0.15, 3.74; I2 = 94 %), agility (-1.49; 95% CL -2.27, -0.71; I2 = 80%), and repeated sprint ability (-1.19; 95% CL - 2.17, -0.21; I2= 53%).There was a moderate beneficial effect on 10- and 20-m sprint performance (-0.89; 95 % CL -1.7, -0.07; I2 =88%), jump height (0.68; 95% CL 0.03, 1.33; I2= 79%), and intermittent endurance (0.61; 95% CL 0.17, 1.05; I2= 0%). The results also showed greater positive effects on specific skills (specific endurance and agility tests and techniques) after SSG when compared with generic or agility training. Small-sided games may represent an effective strategy of multicomponent training that can induce greater positive effects on specific skills tasks when compared with interval or agility training and moderate to large improvements in team sport-related physical fitness.

Validation of three short physical activity questionnaires with accelerometers among university students in Spain.

Abstract: Background Physical activity (PA) in university students has not been analyzed with specific questionnaires tailored to this population. Therefore, the purpose of this study was to analyze the validity of three PA questionnaires developed on other populations comparing with accelerometer values: counts and moderate to vigorous PA (MVPA) calculated with uniaxial and triaxial cut points. Methods One hundred and forty-five university students (of whom, 92 women) from Spain wore an accelerometer GT3X or GTX+ to collect PA data of 7 full days. Three questionnaires, Physical Activity Questionnaire for Adults (PAQ-AD), Assessment of Physical Activity Questionnaire (APALQ), and the International Physical Activity Questionnaire Short Form (IPAQ-SF) were administrated jointly with the collection of accelerometer values. Finally, after the application of inclusion criteria, data from 95 participants (62 women) with a mean age of 21.96±2.33 years were analyzed to compare the instruments measures. Results The correlational analysis showed that PAQ-AD (0.44-0.56) and IPAQ-SF (0.26-0.69) questionnaires were significantly related to accelerometers scores: counts, uniaxial MVPA and triaxial MVPA. Conversely, APALQ displayed no significant relations for males with accelerometers scores for MVPA created with both cut points. Conclusions PAQ-AD and IPAQ-SF questionnaires have shown adequate validity to use with Spanish university students. The use of counts to validate self-report data in order to reduce the variability display by MVPA created with different cut points is discussed. Finally, validated instruments to measure PA in university students will allow implementation of strategies for PA promotion based on reliable data.

Rates and risk factors of injury in CrossFit: a prospective cohort study

Abstract: BACKGROUND: CrossFitTM is a strength and conditioning programme that has gained widespread popularity since its inception approximately 15 years ago. However, at present little is known about the level of injury risk associated with this form of training. Movement competency, assessed using the Functional Movement ScreenTM (FMS), has been identified as a risk factor for injury in numerous athletic populations, but its role in CrossFit participants is currently unclear. The aim of this study was to evaluate the level of injury risk associated with CrossFit training, and examine the influence of a number of potential risk factors (including movement competency). METHODS: A cohort of 117 CrossFit participants were followed prospectively for 12 weeks. Participants' characteristics, previous injury history and training experience were recorded at baseline, and an FMS assessment was conducted. RESULTS: The overall injury incidence rate was 2.10 per 1000 training hours (90% Confidence Limits: 1.32 - 3.33). A multivariate Poisson regression model identified males (rate ratio [RR]: 4.44 ×/÷ 3.30, very likely harmful) and those with previous injuries (RR: 2.35 ×/÷ 2.37, likely harmful) as having a higher injury risk. Inferences relating to FMS variables were unclear in the multivariate model, although number of asymmetries was a clear risk factor in a univariate model (RR per two additional asymmetries: 2.62 ×/÷ 1.53, likely harmful). CONCLUSIONS: The injury incidence rate associated with CrossFit training was low, and comparable to other forms of recreational fitness activities. Previous injury and gender were identified as risk factors for injury, whilst the role of movement competency in this setting warrants further investigation. Language: en

Effects on power, strength and lean body mass of menstrual/oral contraceptive cycle based resistance training

Abstract: BACKGROUND: The purpose of this study was to investigate the effects of menstrual and oral contraceptive cycle on a high frequency periodized leg resistance training in trained women. METHODS: Two ...

Effect of isometric handgrip training on resting blood pressure in adults: a meta-analysis of randomized controlled trials.

Abstract: INTRODUCTION The aims of this study were to update the meta-analysis of the effect of isometric handgrip (IHG) training on resting systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) in healthy adults, and to analyze the association between IHG training and participants with different initial BP status. EVIDENCE ACQUISITION PubMed, EMBASE, and Cochrane library were searched for eligible studies until Nov. 24, 2014. Cochran's Q statistic and the I2 statistic were used to assess the heterogeneity among included studies, and for the homogeneous outcomes (P≥0.05 and I2<50%) a fixed-effects model was selected for meta-analysis, while a random-effects model was applied for heterogeneous outcomes (P<0.05 or I2≥50%). Mean difference (MD) with 95% confidence interval (CI) was calculated to evaluate the effects of IHR on participants. EVIDENCE SYNTHESIS A total of 7 trials from 6 articles were included, consisting of 157 subjects. The results suggested that SBP (MD=-8.33, 95% CI: -11.19 to -5.46; P<0.01) and DBP (MD=-3.93, 95% CI: -6.14 to -1.72; P<0.01) were significantly decreased in IHG training group compared with control group. In subgroup analysis, SBP, DBP, and HR were all significantly decreased in prehypertensive subjects (P<0.01). In medicated hypertensive subgroup and normotensive subgroup, only SBP and DBP were significantly reduced (P<0.01). CONCLUSIONS IHG training lowers resting SBP and DBP in healthy adults, and IHG training may be an efficacious form of clinical treatment or prevention of hypertension.

Match outcome and sprinting activities in match play by elite German soccer players.

Abstract: BACKGROUND The aim of the study was to examine the ways playing positions and match outcome (ie win, draw, loss) affect the sprint distance covered and the number of sprints performed by German Bundesliga soccer players METHODS Match performance data were collected from 350 soccer players competing in the German Bundesliga during the 2014/2015 domestic season A total of 4393 individual match observations were undertaken on outfield players The analysis was carried using the Impire AG motion analysis system with records of all movements of players in all the 306 matches The recorded variables included total sprint distance covered and the total number of sprints in offensive and defensive play The conformity assessment was carried out with the Shapiro-Wilk test (P≤001) To compare mean values of the examined variables a two-way ANOVA was used The differences between pairs of means were verified with Fisher's LSD RESULTS The analysis of the covered sprint distance and the number of performed sprints showed that central defenders and full-backs covered shorter distances in won matches than in lost matches (P≤005) Furthermore, forwards and wide midfielders covered significantly longer sprint distances in won matches than in lost matches (P≤005) CONCLUSIONS The match outcome may be viewed as a measure of performance accomplishment and, hence, it may influence the sprinting efforts made by players

Anthropometric and physical performance characteristics of professional handball players: influence of playing position.

Abstract: BACKGROUND The aims of the study were to examine the anthropometric and physical performance characteristics of professional handball players classified by playing position. METHODS Twenty-one competitors (age: 25.2±5.1 years) were categorized as backs, pivots, wings or goalkeepers. Measures included anthropometrics (body height and mass), scores on the Yo-Yo Intermittent Recovery Test (total distance covered, TD), repeated-sprint ability (6 repetitions of 2x15-m shuttle sprints with recording of best time for a single trial, RSAbest) and performance on a complex handball test (HBKT) of throw slap (TS) and throw jump (TJ) with and without precision. RESULTS The anthropometric data revealed a significantly lower body height for wings and pivots than for goalkeepers. Wings, pivots and goalkeepers were significantly shorter than backs, but had a similar BMI. The TD was greater for the wings (2.400 m) than for backs (1.832 m) and pivots (2.067m). Wings also achieved a better RSAbest (5.41 s) than backs (5.68 s) or pivots (5.82 s). Body height was significantly related to throw slap (TS) and jump (JT) (r=0.53, P<0.01; r=0.51, P<0.01 respectively). No significant difference (P=0.675; η2=0.009) was seen between JT with precision and JT without precision. CONCLUSIONS Substantial differences of body build and physical performance between playing positions underline the importance of a careful assignment of such positions and the development of position-specific training for professional handball players by modifying both intermittent aerobic and anaerobic endurance components of training sessions.

Differences in anthropometric characteristics in relation to throwing velocity and competitive level in professional male team handball: a tool for talent profiling.

Abstract: Background The primary aim of the study was to examine the anthropometric characteristics as well as throwing and sprinting performance of professional handball players classified by playing position and competition level. Methods 21 male players (age: 25.2±5.1 years) from the first German handball league (FGL) and 34 male players (age: 26.1±4.1 years) from the third German handball league (TGL) were categorized as backs, pivots, wings and goalkeepers. Measurements included anthropometric data (height, mass and body mass index (BMI)), throwing and sprinting performance selected out of a complex handball test (HBCT), which was conducted twice (2 rounds). During the HBCT, the subjects performed two sprints (10, 20 m), two standing throws with run-up (ST) and four vertical jump throws (VJT) over a hurdle (20 cm) with and without precision for goal shot. Results The anthropometric data revealed a significantly (P=0.038 and η2=0.079) shorter body height for TGL than for FGL players. In the cohort of first league athletes the pivots were the tallest (1.98±0.04 m), backs in the third league showed the maximum body height (1.90±0.05 m). Regarding body mass, pivots were the heaviest players independent from the league membership. The FGL players showed a significantly (P 0.10) higher throwing velocity in all type of throws. Body height was significantly related to ST (r=0.53) and VJT (r=0.52) in the first round of HBCT but only for the FGL athletes. Throwing velocity was also correlated with BMI (r=-0.50) among the TGL players. Conclusions Substantial differences of body characteristics, throwing and sprinting performance between playing positions and competitive levels underline the importance of a careful scouting and position-specific training for professional handball players.

High-intensity interval training and athletic performance in Taekwondo athletes.

Abstract: BACKGROUND The purpose of this study was to determine the effects of high-intensity interval training (HIIT) on athletic performance in Taekwondo athletes. METHODS Thirty-three male and female collegiate Taekwondo athletes were randomly divided into a HIIT group (N.=16) or a high-intensity continuous running (HICR) group (N.=17). The HIIT group undertook training of high-intensity sprints interspersed with active rest periods whilst the HICR group participated in high-intensity running for a continuous period. Both groups completed 11 sessions over 4 weeks. Physique, body composition, Wingate anaerobic test and VO2max test were measured. The vertical jump test, agility T-test and sit-ups were used to assess physical fitness. Repeated measures ANCOVAs with sex as a covariate were applied and significant level was set at 0.05. RESULTS Following 11 sessions of training, significant improvements in anaerobic peak power (P<0.05), relative peak power (P<0.05), and mean power (P<0.05) were observed only in HIIT group compared to HICR group. A greater improvement of aerobic capacity was observed in HIIT group (8.8%) compared to the HICR group (1.7%). In relation to physical fitness, the HIIT group improved in the vertical jump while the HICR group did not change. Both the HIIT and HICR groups showed greater improvements in T-test and sit-ups during the intervention period. CONCLUSIONS This study shows the effectiveness of eleven sessions of HIIT in producing significant improvements in anaerobic capacity relevant to successful Taekwondo competition performance in collegiate Taekwondo athletes. This could inform the future planning of Taekwondo athletes' pre-competition training, specifically the influence of training intensity on anaerobic capacity.

Cross-sectional relationships between sedentary behavior and frailty in older adults

Abstract: Background The aim of this study was to analyze the association between frailty and sedentary behavior and to examine the discriminative ability of sedentary behavior in screening frailty in older adults. Methods This was a cross-sectional study based on data from an epidemiologic population-based household survey involving 316 community-dwelling older adults (≥60 years) of both sexes (173 women and 143 men). The frailty was measured from an adapted version of the criteria proposed by Fried et al. in 2001, which is based on the presence of three or more of the following components: shrinking, weakness, poor endurance/exhaustion, slowness and low activity. Sedentary behavior was determined by the International Physical Activity Questionnaire (long version). Results The prevalence of frailty was 23.8%, and the average time in sedentary behavior was 6.1±3.2 h/day. Sedentary behavior was independently and positively associated with frailty (PR=1.10; 95% CI: 1.02-1.19; P=0.013). The ROC curve showed that the sedentary behavior could discriminate frail older adults (AUC=0.66; 95% CI: 0.61-0.72), and the best cutoff point was 7 h/day (sensitivity =54% and specificity =75%). Conclusions Frailty is strongly associated with sedentary behavior. Sedentary behavior can be a potential marker in screening of frailty in community-dwelling older adults. Our findings suggest that reducing the time with sedentary behavior and increasing the time with physical activity may prevent frailty syndrome.

Effects of a Whatsapp-delivered physical activity intervention to enhance health-related physical fitness components and cardiovascular disease risk factors in older adults.

Abstract: Background This pilot study evaluated the feasibility and preliminary effectiveness of a 10-week WhatsApp-based intervention aimed at enhancing health-related physical fitness components and cardiovascular disease (CVD) risk factors compared with a face-to-face condition. Methods Participants (N.=32) were assigned to one of three groups: training group (N.=16), mobile group (N.=7) and control group (N.=9). Training group and mobile group performed the same training program, based on strength training with elastics bands and aerobic exercise, during 10 weeks; only the delivery mode differed. Results The mobile group increased handgrip strength, aerobic capacity and decreased systolic blood pressure and heart rate after exercise though there were no significant differences respect to control group. The training group decreased significantly systolic blood pressure (P=0.038), diastolic blood pressure (P=0.005), mean arterial pressure (P=0.006) and heart rate after exercise (P=0.002), respect to control group. Conclusions Comparison between training and mobile group showed that WhatsApp-based physical activity intervention was less effective than face-to-face condition. The results indicate that the use of an online social network produced slight changes in some health-related physical fitness components and CVD risk factors.

Body composition and size in sprint athletes.

Abstract: Background The aims of the present study were to assess competitive sprinters' body size and composition and to determine their impact on performance. Methods Ninety-eight competitive male sprinters (100 m) participated in this cross-sectional study. A series of measurements was directly taken and data on muscular strength and power tests were self-reported. Body composition was assessed by skinfold method and somatotype was calculated by the Heath-Carter anthropometric method. Sprinters were classified into three groups depending on their personal best time and comparisons were performed between the athletes in the top and in the bottom tertiles. Relationships between anthropometric traits and performance were assessed by Pearson's correlation coefficients. Results Top sprinters had significantly greater body mass index, relaxed and contracted upper arm girths, thigh and calf girths, fat free mass and fat free mass index, and lower ectomorphy than the lowest tertile. Strength and power were significantly higher. Personal best time was significantly correlated with several anthropometric traits and indices of lean body mass. Conclusions Body size, composition and somatotype differ between performance levels in speed running. Being less ectomorphic, with a greater fat free mass and strength, can explain significant differences in sprinting performances. The results presented in this study provide a point of reference about sprinter characteristics, which can help coaches and sport scientists to improve sprinter performance.

Extracorporeal shockwaves therapy versus hyaluronic acid injection for the treatment of painful non-calcific rotator cuff tendinopathies: preliminary results.

Abstract: BACKGROUND Rotator cuff tendinopathy is the most common cause of painful shoulder. The treatment is mainly conservative and several therapeutic approaches have been proposed, including NSAIDs, physiotherapy, injections and physical therapies. The aim of the current study was to compare the clinical effectiveness of low molecular weight hyaluronic acid (LMW-HA) injection versus low-energy extracorporeal shock-wave therapy (ESWT) until 3 months of follow-up for the management of painful non-calcific rotator cuff tendinopathies, evaluating also the trend over time between the groups. METHODS A total of 34 patients affected by painful rotator cuff tendinopathy were randomly divided into 2 groups of 17 individuals. The first group (group A; mean age 58.2 years) underwent 3 injections of LMW-HA (Hyalgan®, 500-730 kDa), while in the second group (group B; mean age 58.5 years) the treatment protocol consisted of 4 sessions of low-energy ESWT. Pain level and function were assessed with the DASH and Constant-Murley questionnaires. Parameters were evaluated at baseline (V0), at the end of the treatment (V1) and after 3 months of follow-up (V2). RESULTS Patients of both groups achieved statistically significant improve in pain and function (P<0.0001). Clinical outcome shows a different trend in time between group A and group B for DASH and Constant-Murley questionnaires. CONCLUSIONS LMW-HA and low-energy ESWT are effective and safe in patients suffering from non-calcific rotator cuff tendinopathy until 3 months of follow-up. Intra-articular injections of LMW-HA provide prompt clinical improvement compared to ESWT, which results in more gradual improvement over time.

Session-RPE for quantifying load of different youth taekwondo training sessions

Abstract: BACKGROUND The session rating of perceived exertion (session-RPE) proved to be a valuable method to quantify the internal training load (ITL) in taekwondo. However, no study validated this method in youth taekwondo athletes performing different training sessions. Thus this study aimed at evaluating the reliability of the session-RPE to monitor the ITL of prepubescent taekwondo athletes during pre-competitive (PC) and competitive (C) training sessions. METHODS Five female (age: 12.0±0.7 y; height: 1.54±0.08 m; body mass: 48.8±7.3 kg) and four male (age: 12.0±0.8 yrs; height: 1.55±0.07 m; body mass: 47.3±5.3 kg) taekwondo athletes were monitored during 100 individual sessions (PC: N.=33; C: N.=67). The Edwards' HR method was used as reference measure of ITL; the CR-10 RPE scale was administered at 1- and 30-minutes from the end of each session. RESULTS No difference for gender emerged. The ITLs of C (Edwards: 228±40 arbitrary units, AU) resulted higher than that of PC (192±26 AU; P=0.04). Although all training typologies and data collections achieved significant correlations between Edwards' and session-RPE methods, a large relationship (r =0.71, P<0.001) emerged only for PC sessions evaluated at 30 minutes of the recovery phases. CONCLUSIONS Findings support coaches of prepubescent taekwondo athletes to successfully use session-RPE to monitor the ITL of different training typologies. However, PC training evaluated at 30 minutes of the recovery phase represents the best condition for a highly reliable ITL perception.

The effect of acute fatigue on countermovement jump performance in rugby union players during preseason

Abstract: A countermovement jump (CMJ) is routinely used in many sporting settings to provide a functional measure of neuromuscular fatigue. However, the variables that are most sensitive to fatigue remain somewhat unclear (Gathercole, Sporer, Stellingwerff, and Sleivert, 2015, International Journal of Sports Physiology and Performance, 10, 84–92). The aim of this study was to examine the usefulness of selected CMJ variables to monitor the post-exercise fatigue and recovery cycle. With institutional ethics approval, nine male academy rugby union players performed five CMJ trials on three occasions, at baseline, 24 h and 48 h post-baseline. The fatiguing protocol consisted of a typical intense training day during the preseason period (speed/skills training AM and resistance training PM). A total of 21 CMJ variables were derived from the force–time curve, 15 relating to output (CMJ-OUT) and 6 relating to the mechanics of the jump (CMJ-MEC). Data were analysed using a repeated measures one-way ANOVA with Bonferroni post hoc comparisons. There were no significant differences for any CMJ variable at the 24 h time point. At 48 h, three CMJ-MEC variables (eccentric duration, total duration and the force at zero velocity) demonstrated a significant decrement in performance when compared to baseline (P < 0.05). Neuromuscular fatigue may manifest itself as an altered movement strategy rather than a simple reduction in physical output, when measured using a CMJ. Practitioners are therefore advised to incorporate CMJ-MEC variables when trying to identify subtle changes in the bimodal recovery pattern associated with stretch-shortening cycle induced fatigue. Such information may help with the prescription of optimal training loads, whilst attempting to avoid overtraining and injury.

Portable open-circuit spirometry systems.

Abstract: Background The purpose of this review is to describe the evolution of portable open-circuit spirometry systems, and discuss their validity, reliability, and principles of operation. Methods Eleven devices were selected for review: the Oxylog, Aerosport KB1-C, Cosmed K2, Cosmed K4RQ, Cosmed K4b2, MetaMax I, MetaMax II, Metamax3B/VmaxST, Medgraphics VO2000, Oxycon Mobile I and Oxycon Mobile II. The validity (compared to the Douglas bag method [DBM]) and reliability of each device for measuring VO2 was summarized. Results Mean differences in resting measurements of VO2 were within ±0.05 L/min for all devices except one (difference of 0.17 L/min). When compared to the DBM, VO2 differences for all devices ranged from 0.01 L/min to 0.29 L/min during submaximal intensity exercise and from 0.01 L/min to 0.36 L/min during vigorous/maximal intensity. During submaximal and maximal intensities, ICC ranged from 0.66-0.99 and CV ranged from 2.0-14.2%. Of these devices, four used breath-by-breath technology and six used micro-proportional sampling technology. Validity and reliability of devices did not seem to differ between methods of gas collection. Conclusions Of the three commercially available devices in 2015, all were found to be reliable. Two of the three systems (Cosmed K4b2 and Oxycon Mobile II) provided valid estimates of VO2 (mean values within ±0.10 L/min of DBM) during rest, and submaximal and maximal intensities, while the MetaMax3B slightly overestimated VO2, particularly at maximal exercise.

Effects of volume-based overload plyometric training on maximal-intensity exercise adaptations in young basketball players.

Abstract: Background: The aim of the present study was to compare maximal-intensity exercise adaptations in young basketball players (who were strong individuals at baseline) participating in regular basketball training versus regular plus a volume-based plyometric training program in the pre-season period. Methods: Young basketball players were recruited and assigned either to a plyometric with regular basketball training group (experimental group [EG]; N.=8), or a basketball training only group (control group [CG] ; N.=8). The athletes in EG performed periodized (i.e., from 117 to 183 jumps per session) plyometric training for eight weeks. Before and after the intervention, players were assessed in vertical and broad jump, change of direction, maximal strength and a 60-meter sprint test. Results: No significant improvements were found in the CG, while the EG improved vertical jump (effect size [ES] 2.8), broad jump (ES=2.4), agility T test (ES=2.2), Illinois agility test (ES=1.4), maximal strength (ES=1.8), and 60-m sprint (ES=1.6) (P < 0.05) after intervention, and the improvements were greater compared to the CG (P < 0.05). Conclusions: Plyometric training in addition to regular basketball practice can lead to meaningful improvements in maximal-intensity exercise adaptations among young basketball players during the pre-season.

Incidence of musculoskeletal sport injuries in a sample of male and female recreational paddle-tennis players.

Abstract: Background Nowadays paddle-tennis is practiced by the Spanish population, not only in a professional or semi-professional way, but also as a recreational sport. As occurs in tennis, the repetition of specific actions and gestures in paddle-tennis could be a factor associated with one or more types of musculoskeletal injuries in this population. The aim of this research was to describe the incidence and location of musculoskeletal injuries in a sample of Spanish recreational paddle-tennis and to explore a possible causality injury model, focusing on gender contribution. Methods The sample was composed of 113 active paddle-tennis players, of whom 47.78% were men. The participants were asked about the injuries they had suffered during their paddle participation. Other variables such as age, physical position in the game and level of ability were taken into account. Results 85.4% of the players reported any sport paddle injury. The elbow and the lower back have been shown as the most common regions of injury, followed by knee and shoulder injuries. Female group reported a higher injury incidence due to playing paddle-tennis (OR=0.169; P=0.008). Significant differences also existed between the genders for calf injury location (OR=0.208; P=0.020). A global injury model explaining 22.5% of the variance has been observed. Gender seems to explain 7.4% of the variance. Conclusions Being a medium-aged weighty right-handed woman seems to be the profile more likely to report paddle-tennis related musculoskeletal injuries. A lack of literature regarding paddle-tennis related injuries has been observed. It could be said that our results contribute substantially in this field.

Agility and change of direction in soccer: differences according to the player ages.

Abstract: BACKGROUND The goal of this study was to compare the changes of direction speed (CODS) and reactive agility (RA) in soccer players of different ages, in order to optimize the best training of these skills. METHODS One hundred eighty-seven players, divided into bi-annual age-groups, U12, U14, U16 and U18, performed two tests: Y-Agility Test, carried out in planned and reactive mode (Y-PLAN and Y-REAC) and Illinois for Change of Direction Test (ICODT). Difference between Y-REAC minus Y-PLAN represents the index of reactivity (REAC-INDEX). RESULTS MANOVA showed significant differences among groups (F3,182=14.591; P<0.01; η2p=0.244). Y-PLAN showed significant differences only between U12 and the other groups (P<0.01). ICODT results were significantly different between the groups U12 and U14 and the other groups (P<0.01). Significant Pearson's correlations between Y-TEST and ICODT, for the three categories of young players (0.398 P<0.05; 0.615 P<0.01; 0.608 P<0.01 respectively), were found, whereas no significant correlation was found in U18 group. CONCLUSIONS The best performance of Y-PLAN and ICODT, through age, depends on physical skill level, whereas the best RA results depend on technique and experience that help the players to use anticipatory skill. The high correlations between CODS and RA performances, differently than adult athletes, suggest that an effective work program for young players may include RA and CODS training at the same time.

Technical and physical determinants of soccer match-play performance in elite youth soccer players.

Abstract: Background The aim of this study was to evaluate whether physical performance characteristics could be a better predictor than technical skills in determining the technical level of county soccer players in a match situation. Methods With institutional ethics approval, 25 male youth soccer players aged 16-18.5 years from a professional soccer academy in South East Asia were selected and height and body mass were recorded. Players were tested for sexual maturity (pubertal development scale [PDS] self-assessment), aerobic capacity (yo-yo intermittent recovery test level 1 [YYIR1]), repeated sprint ability (7 x 35 m sprints) acceleration (15 m sprint) and four soccer skills tests (dribble with pass, dribbling speed, passing and shooting accuracy). Players' technical ability during match play was assessed in small-sided games of soccer (5 v 5) using a novel game technical scoring chart (scoring chart completed by coaches to assess technical performance in a match situation) developed from criteria (e.g., first touch, dribbling and two footedness) used by youth soccer coaches for talent identification. Results A Spearman's rank correlation showed the YYIR1 test and 15 m sprint test were limited in predicting technical match performance (r=0.03, P=0.88, r=-0.23, P=0.32 respectively). A Pearson product moment correlation showed that the repeated sprint test was also limited in predicting technical match performance (r=-0.34, P=0.14). A dribbling skill with a pass was found to be the best determinant of a player's technical ability in a match (r=-0.57, P=0.00). Conclusions Talent identification and selection programs in Asian youth soccer should include a dribbling skill performed with a pass.

Predicting race time in male amateur marathon runners.

Abstract: BACKGROUND The aim of the study was to analyze the relationship between anthropometry, training characteristics, muscular strength and effort-related cardiovascular response and marathon race time in male amateur runners. METHODS A total of 84 male amateur marathon runners aged between 23 and 70 years took part in this study (41.0±9.5 years). All of them competed in the 2013 edition of the Madrid Marathon with a finish time between 169.8 and 316 minutes (226.0±28.5 minutes). Age, running experience, number of marathon races finished, mean kilometers run weekly in the last three months, and previous personal best time in the 10 km, half marathon and marathon were recorded. Moreover, anthropometric characteristics, and the results from the Ruffier Test and a whole-body isometric force test were measured. After the marathon, the race time was registered. RESULTS Training volume (r=-0.479; P=0.001), previous running milestones (marathon r=0.756; half-marathon r=0.812; 10-km r=0.732; P 0.50. The best, including body fat percentage, heart rate change during the recovery after the Ruffier Test and the half-marathon race time, was strongly correlated with real marathon performance (r=0.77; P<0.001). A second regression model was proposed replacing the half-marathon performance with the 10-km race time, reducing the correlation to 0.73 (P<0.001). CONCLUSIONS Marathon performance could be partially predicted by two different equations, including body fat percentage, recovery heart rate in the Ruffier Test and a half-marathon or 10-km performance.

Development of maximal speed sprinting performance with changes in vertical, leg and joint stiffness.

Abstract: Background This study aimed to clarify the changes in stiffness variables when maximal speed sprinting performance was developed through long-term training. Methods Nine well-trained male athletes performed maximal effort 60-m sprints before and after the completion of six months of winter training. In both experiments, sprinting motion at maximal speed was recorded with a high-speed camera and simultaneously ground reaction force (GRF) was measured. Spatiotemporal and stiffness variables were then calculated. Results Sprinting speed was significantly developed (P=0.001) through longer step length (P=0.049). While the leg stiffness did not change (from -539±126 to -558±180 N/kg/m) (P=0.686), the vertical stiffness significantly increased (P=0.001) from -1507±346 to -2357±704 N/kg/m due to increase and decrease in vertical GRF and descent of whole body center of gravity, respectively. Moreover, whereas knee joint stiffness remained constant (from -0.228±0.080 to -0.213±0.084 Nm/kg/°) (P=0.448), ankle joint stiffness was significantly developed (P=0.002) from -0.165±0.031 to -0.210±0.032 Nm/kg/° due to a respective increase and decrease in ankle plantarflexion moment and ankle dorsiflexion angle. Conclusions The results demonstrate that the development of maximal speed sprinting performance through longer step length is accompanied by increases in vertical and ankle joint stiffness, and this shows the importance of vertical and ankle stiffness for improving maximal speed sprinting performance. Findings of this study may assist with the planning of training programs for athletes.

Who jumps the highest? Anthropometric and physiological correlations of vertical jump in youth elite female volleyball players.

Abstract: BACKGROUND: The aim of the present study was to examine the relationship of vertical jump (Abalakov jump, AJ) with anthropometric and physiological parameters in youth elite female volleyball players. METHODS: Seventy-two selected volleyball players from the region of Athens (age 13.3±0.7 yrs, body mass 62.0±7.2 kg, height 171.5±5.7 cm, body fat 21.2±4.5%), classified into quartiles according to AJ performance (group A, 21.4-26.5 cm; group B, 26.8-29.9 cm; group C, 30.5-33.7 cm; group D, 33.8-45.9 cm), performed a series of physical fitness tests. RESULTS: AJ was correlated with anthropometric - age at peak height velocity (APHV, r=0.38, p<0.001), body mass (r=-0.43, p<0.001), body mass index (BMI, r=-0.37, p<0.001) and body fat percentage (BF, r=-0.64, p<0.001) - and with physiological parameters - isometric strength (r=0.50, p<0.001), squat jump (SJ, r=0.92, p<0.001), countermovement jump (CMJ, r=0.95, p<0.001), Bosco (r=0.70, p<0.001), mean power (Pmean, r=0.61, p<0.001) and fatigue index (r=-0.33, p=0.005) in the Wingate anaerobic test (WAnT). A one-way analysis of variance showed significant differences in APHV, chronological age, body mass, BMI, BF, aerobic capacity (step test and physical working capacity at heart rate 170 bpm), Pmean in the WAnT, isometric strength, SJ, CMJ and 30 s Bosco test (p<0.05). A Bonferroni post-hoc analysis revealed that D group had older APHV and lower BMI, better aerobic capacity, isometric strength, SJ, CMJ, performance in the Bosco test and Pmean in the WAnT, was older, lighter than A, B and C groups (p<0.05). CONCLUSION: Both the findings of the comparison among groups differing for AJ and the correlation analysis highlighted the negative role of excess body mass and fat, and the positive role of muscle strength and power on AJ. Also, there was indication that volleyball players that jumped the highest were those who matured later than others.

Effect of pre-task music on sports or exercise performance.

Abstract: Introduction Pre-task music is a very common strategy among sports competitors. However, as opposed to in-task music, the scientific evidence to support its ergogenic effects on either sports or exercise performance is limited. This brief review critically addresses the existing literature investigating the effects of pre-task music on sports and exercise performance, focusing on the methods and results of experimental studies, and offers basic and practical recommendations. Evidence acquisition In July 2015, a comprehensive literature search was performed in Web of Science, PubMed, and Google Scholar using the following key words in combination: "pre-task music," "pre-test music," "pre-exercise music," "exercise performance," "sports performance." The literature search was further expanded by both hand searching review articles on the topic and by searching the reference lists from the articles retrieved for any relevant references. Overall, a total of 15 studies in 14 articles were included. Evidence synthesis Pre-task music research has been unsystematic, methodologically limited and infrequent. Using this review as a starting point to overcome previous methodological limitations when designing future experiments may contribute to the development of pre-task music research, which is still in its infancy. Conclusions Currently, there is no sufficient evidence to support the overall ergogenic effects of pre-task music on sports or exercise performance. Nonetheless, pre-task music has showed a likely ergogenic effect on shorter and predominantly anaerobic tasks such as grip strength, Wingate test, and short-duration sports or sports-like tasks, in contrast to longer and predominantly aerobic tasks.

The kinematics of table tennis racquet: differences between topspin strokes.

Abstract: Background Studies of shot kinematics in table tennis have not been sufficiently described in the literature. The assessment of the racquet trajectory, its speed and time characteristics makes it possible to emphasize on certain technical elements in the training process in order, for example, to increase strength, speed of rotation or speed of the shot while maintaining its accuracy. The aim of this work was to measure selected kinematic parameters of table tennis racquet during forehand and backhand topspin shots, while considering the differences between these strokes in table tennis. Methods The measurements took place in a certified biomechanical laboratory using a motion analysis system. The study involved 12 female table tennis players in high-level sports training and performance. Each subject had to complete series of six tasks, presenting different varieties of topspin shots. Results The longest racquet trajectory was related to forehand shots, shots played against a ball with backspin and winner shots. The maximum racquet velocity was precisely in the moment of impact with the ball. The individual of velocity and distance were larger in the direction of the acting force, depending on the individual shot. Conclusions Changing the type of topspin shot requires changes of time, velocity and primarily distance parameters as well as the direction of the playing racquet. The maximum speed of the racquet occurring at the moment of the impact is probably the most important principle in playing technique. The results can be directly used in improving training of table tennis techniques, especially in the application and use of topspin shots.

Effects of one night sleep deprivation on selective attention and isometric force in adolescent Karate athletes

Abstract: BACKGROUND: Most of the available literature related to aspects of sleep-deprivation is primarily focused on memory and learning and studies regarding its effects on selective- attention and/or physical performance especially the isometric-force are scarce. Moreover, the available literature included general population or some team sports (eg; volleyball). However, only few studies were done on athletes involved in combat sports (eg; Karate). The aim of the present study was to determine the effects of a total one-night-sleep- deprivation (NSD) on activator- and inhibitor-processes of selective-attention and on maximal-isometric-force in Karate athletes. METHODS: Twelve Karate boys (age mean±SD: 16.9±0.8 Yrs) were included. The protocol consists of two successive sessions: a normal-night-sleep (NNS) and a total one- NSD. After each night, athletes performed selective-attention and muscle-strength-tests during the same following three periods (P) of the day: P1NNS or P1NSD: 8-9 am; P2NNS or P2NSD: 12 am-1 pm; P3NNS or P3NSD: 4-5 pm. The activator [simple- and choice-reaction- times (SRT, CRT, respectively)] and inhibitor (negative-priming) processes were evaluated "Superlab4.5 software, Cedrus, San Pedro, USA". Maximal-force and maximal-force-time (MFT) of brachial biceps isometric-contraction were evaluated (dynamometer Globus ergo system®; Italy). Data were expressed as mean±SD. A non-parametric test was used to evaluate the sessions (NNS vs. SND for the same period) and time (P1NNS vs. NSD periods') effects. RESULTS: All athletes completed tests realized after NNS. 12, 11 and 4th athletes finished, respectively, P1NSD, P2NSD and P3NSD. Sessions effects: no statistical significant difference was found. Time effects: i) Significant increase of SRT at P2NSD vs. P1NNS (respectively, 345±47 vs. 317±33 ms); ii) Significant increase of MFT at P2NSD vs. P1NNS (respectively, 2172±260 vs.1885±292 ms) and iii) No significant changes of CRT; negative- priming reaction-time or MFT data. CONCLUSION: Total one-NSD affects both activator-processes of selective-attention and maximal-isometric-strength, two qualities often used in Karate sports. Language: en

Is muscular strength balance influenced by menstrual cycle in female soccer players

Abstract: Background Muscular strength imbalance is an important risk factor for ACL injury, but it is not clear the impact of menstrual cycle on muscular strength balance. Our aims were to compare muscular balance (hamstring-to-quadriceps peak torque strength balance ratio) between luteal and follicular phases and compare gender differences relative to strength balance to observe possible fluctuations in strength balance ratio. Methods Thirty-eight soccer athletes (26 women and 12 men) took part in this study. Athletes participated in two identical isokinetic strength evaluations for both knee (non-dominant [ND] and dominant [D]). Peak torque for quadriceps and hamstring muscles were measured in concentric mode and hamstring-to-quadriceps peak torque strength balance ratio calculated. Results Women had significantly lower hamstring-to-quadriceps peak torque strength balance ratio during the follicular compared to luteal phase, for the ND limb (P=0.011). However, no differences, between luteal and follicular phases, were observed in the D limb. In men, no difference in strength balance ratios was found between the ND and D limbs. Conclusions These data may be useful in prevention programs for knee (ACL) injuries among soccer female athletes.

Acute effects of scapular Kinesio Taping® on shoulder rotator strength, ROM and acromiohumeral distance in asymptomatic overhead athletes.

Abstract: BACKGROUND There is limited information in the literature that shows whether scapular taping has an effect on the acromiohumeral distance (AHD) and shoulder functions. The aim of this study was to investigate the acute effects of scapular Kinesio Taping® on shoulder internal rotation (IR) and external rotation (ER) strength, IR and ER range of motion (ROM) and AHD in asymptomatic overhead athletes. METHODS Forty-one volleyball athletes (24 men, 17 women; mean age: 16.1±1.5 years, body mass: 66.5±9.6 kg, body height: 179.6±8.4 cm, Body Mass Index: 20.5±2.3 kg/m2, time participating in overhead sports activity: 6.2±1.4 h/week, experience in sport: 4.1±2.4 years) were included in this study. Shoulder IR and ER ROM, total rotation ROM, AHD, shoulder isometric IR and ER strength and ER:IR strength ratio of the dominant side were tested before and after taping. RESULTS Scapular taping increased the shoulder IR (P<0.001) and total ROM (P<0.001), AHD (P<0.001), shoulder IR (P=0.002) and ER (P=0.006) strength. ER ROM and ER:IR ratio did not change after taping (P=0.26, P=0.98, respectively). CONCLUSIONS The results of this study suggest that scapular taping could be an effective method for enhancing the acromiohumeral distance, shoulder rotator strength and range of motion. Therefore, scapular taping could be recommended for not only in the asymptomatic athletes' shoulder exercise training but also in the prevention of subacromial impingement syndrome.

A study on level of physical activity, depression, anxiety and stress symptoms among adolescents.

Abstract: BACKGROUND: Inadequate physical activity has adverse health consequences among adolescents. Mental health problem can be developed by lack of physical activity however it is controversial. The current study aimed to examine the association between level of physical activity with depression, anxiety and stress symptoms among adolescents. METHODS:A representative sample of 1747 adolescents (13-14 years) was randomly selected from 6 schools in a south part of Malaysia. Respondents were asked to fill consent form, and questionnaires including Depression Anxiety and Stress Scale-21 and Physical Activity Questionnaire for Adolescents. RESULTS:Majority of respondents (71.9%) was Malay and more than half of the adolescents had low physical activity. About 40% had depression symptoms, followed by anxiety symptoms (65.9%) and stress symptoms (38.5%). Level of physical activity was significantly associated with gender, anxiety and stress (P<0.001). There were no associations with race, religion and depression symptom. CONCLUSIONS:This study provides some evidence among school-going adolescents related to anxiety and stress symptoms and low physical activities. Further studies are needed to show the protection effects of higher physical activity for depression, anxiety and stress symptoms in adolescents.