ATS/ACCP statement on cardiopulmonary exercise testing.

Resistance exercise has been shown to elicit a significant acute hormonal response. It appears that this acute response is more critical to tissue growth and remodelling than chronic changes in resting hormonal concentrations, as many studies have not shown a significant change during resistance training despite increases in muscle strength and hypertrophy. Anabolic hormones such as testosterone and the superfamily of growth hormones (GH) have been shown to be elevated during 15-30 minutes of post-resistance exercise providing an adequate stimulus is present. Protocols high in volume, moderate to high in intensity, using short rest intervals and stressing a large muscle mass, tend to produce the greatest acute hormonal elevations (e.g. testosterone, GH and the catabolic hormone cortisol) compared with low-volume, high-intensity protocols using long rest intervals. Other anabolic hormones such as insulin and insulin-like growth factor-1 (IGF-1) are critical to skeletal muscle growth. Insulin is regulated by blood glucose and amino acid levels. However, circulating IGF-1 elevations have been reported following resistance exercise presumably in response to GH-stimulated hepatic secretion. Recent evidence indicates that muscle isoforms of IGF-1 may play a substantial role in tissue remodelling via up-regulation by mechanical signalling (i.e. increased gene expression resulting from stretch and tension to the muscle cytoskeleton leading to greater protein synthesis rates). Acute elevations in catecholamines are critical to optimal force production and energy liberation during resistance exercise. More recent research has shown the importance of acute hormonal elevations and mechanical stimuli for subsequent up- and down-regulation of cytoplasmic steroid receptors needed to mediate the hormonal effects. Other factors such as nutrition, overtraining, detraining and circadian patterns of hormone secretion are critical to examining the hormonal responses and adaptations to resistance training.

Hormonal Responses and Adaptations to Resistance Exercise and Training

The quest to increase lean body mass is widely pursued by those who lift weights. Research is lacking, however, as to the best approach for maximizing exercise-induced muscle growth. Bodybuilders generally train with moderate loads and fairly short rest intervals that induce high amounts of metabolic stress. Powerlifters, on the other hand, routinely train with high-intensity loads and lengthy rest periods between sets. Although both groups are known to display impressive muscularity, it is not clear which method is superior for hypertrophic gains. It has been shown that many factors mediate the hypertrophic process and that mechanical tension, muscle damage, and metabolic stress all can play a role in exercise-induced muscle growth. Therefore, the purpose of this paper is twofold: (a) to extensively review the literature as to the mechanisms of muscle hypertrophy and their application to exercise training and (b) to draw conclusions from the research as to the optimal protocol for maximizing muscle growth.

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The mechanisms of muscle hypertrophy and their application to resistance training.

During the last nearly 50 years, the blood lactate curve and lactate thresholds (LTs) have become important in the diagnosis of endurance performance. An intense and ongoing debate emerged, which was mainly based on terminology and/or the physiological background of LT concepts. The present review aims at evaluating LTs with regard to their validity in assessing endurance capacity. Additionally, LT concepts shall be integrated within the ‘aerobic-anaerobic transition’ — a framework which has often been used for performance diagnosis and intensity prescriptions in endurance sports. Usually, graded incremental exercise tests, eliciting an exponential rise in blood lactate concentrations (bLa), are used to arrive at lactate curves. A shift of such lactate curves indicates changes in endurance capacity. This very global approach, however, is hindered by several factors that may influence overall lactate levels. In addition, the exclusive use of the entire curve leads to some uncertainty as to the magnitude of endurance gains, which cannot be precisely estimated. This deficiency might be eliminated by the use of LTs. The aerobic-anaerobic transition may serve as a basis for individually assessing endurance performance as well as for prescribing intensities in endurance training. Additionally, several LT approaches may be integrated in this framework. This model consists of two typical breakpoints that are passed during incremental exercise: the intensity at which bLa begin to rise above baseline levels and the highest intensity at which lactate production and elimination are in equilibrium (maximal lactate steady state [MLSS]). Within this review, LTs are considered valid performance indicators when there are strong linear correlations with (simulated) endurance performance. In addition, a close relationship between LT and MLSS indicates validity regarding the prescription of training intensities. A total of 25 different LT concepts were located. All concepts were divided into three categories. Several authors use fixed bLa during incremental exercise to assess endurance performance (category 1). Other LT concepts aim at detecting the first rise in bLa above baseline levels (category 2). The third category consists of threshold concepts that aim at detecting either the MLSS or a rapid/distinct change in the inclination of the blood lactate curve (category 3). Thirty-two studies evaluated the relationship of LTs with performance in (partly simulated) endurance events. The overwhelming majority of those studies reported strong linear correlations, particularly for running events, suggesting a high percentage of common variance between LT and endurance performance. In addition, there is evidence that some LTs can estimate the MLSS. However, from a practical and statistical point of view it would be of interest to know the variability of individual differences between the respective threshold and the MLSS, which is rarely reported. Although there has been frequent and controversial debate on the LT phenomenon during the last three decades, many scientific studies have dealt with LT concepts, their value in assessing endurance performance or in prescribing exercise intensities in endurance training. The presented framework may help to clarify some aspects of the controversy and may give a rationale for performance diagnosis and training prescription in future research as well as in sports practice.

Lactate threshold concepts: how valid are they?

SANCHEZ-MEDINA, L., and J. J. GONZALEZ-BADILLO. Velocity Loss as an Indicator of Neuromuscular Fatigue during Resistance Training. Med. Sci. Sports Exerc., Vol. 43, No. 9, pp. 1725-1734, 2011. Purpose: This study aimed to analyze the acute mechanical and metabolic response to resistance exercise protocols (REP) differing in the number of repetitions (R) performed in each set (S) with respect to the maximum predicted number (P). Methods: Over 21 exercise sessions separated by 48-72 h, 18 strength-trained males (10 in bench press (BP) and 8 in squat (SQ)) performed 1) a progressive test for one-repetition maximum (1RM) and load-velocity profile determination, 2) tests of maximal number of repetitions to failure (12RM, 10RM, 8RM, 6RM, and 4RM), and 3) 15 REP (S R(P): 3 6(12), 3 8(12), 3 10(12), 3 12(12), 3 6(10), 3 8(10), 3 10(10), 3 4(8), 3 6(8), 3 8(8), 3 3(6), 3 4(6), 3 6(6), 3 2(4), 3 4(4)), with 5-min interset rests. Kinematic data were registered by a linear velocity transducer. Blood lactate and ammonia were measured before and after exercise. Results: Mean repetition velocity loss after three sets, loss of velocity pre-post exercise against the 1-mIs j1 load, and countermovement jump height loss (SQ group) were significant for all REP and were highly correlated to each other (r = 0.91-0.97). Velocity loss was significantly greater for BP compared with SQ and strongly correlated to peak postexercise lactate (r = 0.93-0.97) for both SQ and BP. Unlike lactate, ammonia showed a curvilinear response to loss of velocity, only increasing above resting levels when R was at least two repetitions higher than 50% of P. Conclusions: Velocity loss and metabolic stress clearly differs when manipulating the number of repetitions actually performed in each training set. The high correlations found between mechanical (velocity and coun- termovement jump height losses) and metabolic (lactate, ammonia) measures of fatigue support the validity of using velocity loss to

Velocity loss as an indicator of neuromuscular fatigue during resistance training.

SMILIOS, I., T. PILIANIDIS, M. KARAMOUZIS, and S. P. TOKMAKIDIS. Hormonal Responses after Various Resistance Exercise Protocols. Med. Sci. Sports Exerc., Vol. 35, No. 4, pp. 644 – 654, 2003. Purpose: This study examined the effects of the number of sets on testosterone, cortisol, and growth hormone (hGH) responses after maximum strength (MS), muscular hypertrophy (MH), and strength endurance (SE) protocols. Methods: Eleven young men performed multi-joint dynamic exercises using MS (5 reps at 88% of one-repetition maximum (1-RM), 3-min rest) and MH (10 reps at 75% of 1-RM, 2-min rest) protocols with 2, 4, and 6 sets at each exercise; and an SE (15 reps at 60% of 1-RM, 1-min rest) with 2 and 4 sets. Hormonal concentrations were measured before exercise, immediately after, and at 15 and 30 min of recovery. Results: The number of sets did not affect the hormonal responses after the MS protocol. Cortisol and hGH were higher (P 0.05) after the four-set compared with the two-set sessions in the MH and SE protocols. No differences were observed between the six-set and the four-set sessions in the MH protocol. Cortisol and hGH were higher (P 0.05) than the MS after the SE and MH protocols, and only when four and six sets were performed in the latter. hGH was higher than the MH after the SE protocol, whether two or four sets were executed, whereas cortisol (P 0.05) was higher after the SE protocol only when two sets were performed. Testosterone did not change with any workout. Conclusion: The number of sets functions up to a point as a stimulus for increased hormonal concentrations in order to optimize adaptations with MH and SE protocols, and has no effect on a MS protocol. Furthermore, the number of sets may differentiate long-term adaptations with MS, MH, and SE protocols causing distinct hormonal responses. Key Words: STRENGTH, HYPERTROPHY, STRENGTH ENDURANCE, NUMBER OF SETS, TOTAL WORK

Hormonal responses after various resistance exercise protocols.

The present study examined the short-term effects of loaded half squats (HSs) and loaded jump squats (JSs) with low and moderate loads on the squat jump (SJ) and the countermovement jump (CMJ) performance using a contrast training approach. Ten men (mean +/- SD age, 23 +/- 1.8 years) performed the HS and JS exercises twice with loads of 30% of 1 repetition maximum (1RM) (HS30% and JS30%, respectively) and 60% of 1RM (HS60% and JS60%, respectively). On each occasion, 3 sets of 5 repetitions with 3 minutes of rest were performed as fast as possible. Vertical jump performance was measured before exercise, 1 minute after each set, and at the fifth and 10th minutes of recovery. The CMJ increased significantly after the first and second set (3.9%; p < 0.05) compared with preexercise values following the JS30% protocol and 3.3% after the second and third sets of the JS60% protocol. Following the HS60% protocol, CMJ increased after the first and the second sets (3.6%; p < 0.05) compared with preexercise values, whereas SQ increased only after the first set (4.9%; p < 0.05) in this condition. These data show that contrast loading with the use of low and moderate loads can cause a short-term increase in CMJ performance. The applied loads do not seem to present different short-term effects after loaded JSs. When the classic form of dynamic HS exercise is performed, however, at least a moderate load (60% of 1RM) needs to be applied.

Short-term effects of selected exercise and load in contrast training on vertical jump performance.

The purpose of this study was to compare various methods and criteria used to identify the an- aerobic threshold (AT), and to correlate the AT ob- tained with each other and with running performance. Furthermore, a number of additional points throughout the entire range of lactate concentrations (La ) ) were obtained and correlated with performance. A group of 19 runners (mean age 33.7 (SD 9.6) years, height 173 (SD 6.3) cm, body mass 68.3 (SD 5.4) kg, maximal O2 up- take ( _ V O2max) 55.2 (SD 5.9) ml AE kg )1 AE min )1 ) per- formed a maximal multistage treadmill test (1 km AE h )1 every 3.5 min) with blood sampling at the end of each stage while running. All AT points selected (visual (La ) ), 4 mmol AE l )1 (La ) ), 1 mmol AE l )1 above baseline, log-log breakpoint, and 45∞ tangent to the exponential regres- sion) were highly correlated one with another and with performance (r > 0.90) even when there were many diAerences among the AT (P 0.90). These results failed to demonstrate a distinct AT because many points of the curve provided similar information. In- tercorrelations and correlations between AT and per- formance were, however, reduced when AT were ex- pressed as the percentage of maximal treadmill speed obtained at AT or percentage of _ V O2max. This would indicate that diAerent attributes of aerobic performance (i.e. maximal aerobic power, running economy and en- durance) are measured when manipulating units. Thus, coaches should be aware of these results when they prescribe an intensity for training and concentrate more on the physiological consequences of a chosen (La ) ) rather than on a ''threshold''.

Failure to obtain a unique threshold on the blood lactate concentration curve during exercise

This study examined testosterone, cortisol and growth hormone responses in elderly and young men after a strength endurance protocol. Eight elderly (age: 69 +/- 5 yrs) and nine young (age: 23 +/- 1 yrs) males with recreational experience in resistance training performed a strength endurance protocol, which included six exercises. At each exercise, the subjects performed 3 sets of 15 reps at 60 % of 1-RM with a 90 s rest interval between sets. The subjects also participated in a control session. Hormonal and blood lactate concentrations were measured before exercise, immediately after exercise and 15 min after the end of exercise. Blood lactate increased (p 0.05). Growth hormone concentration increased (p<0.05) after resistance exercise compared to the control session in both age groups. This increase was higher (p<0.05) in the young as compared to the elderly group. The above results show that a moderate intensity - high repetition resistance exercise protocol for the improvement of strength endurance, seems to be a sufficient stimulus that increases testosterone, growth hormone and cortisol concentrations in elderly males. These hormonal responses may create an optimal metabolic environment, which improves muscular function after a strength endurance program although the elderly subjects present an attenuated growth hormone response compared to younger ones.

Hormonal responses after a strength endurance resistance exercise protocol in young and elderly males.

We examine the presence of visually regulated control in young, novice long jumpers as they approach the takeoff board The approach run of 27 novice jumpers (age 12–13 years) practising jump training for a short period was video-recorded during competition Findings revealed that young, novice participants adjust the length of the final steps of their approach run, suggesting the presence of visual control Step regulation commenced on the fifth and fourth step from the board for boys and girls respectively Their pattern of footfall variability was found to be comparable to that of skilled long jumpers, although young, novice participants presented slightly higher variability It appears that even a limited period of jump training may contribute to a more consistent run-up as well as to smaller takeoff error, offsetting the limitations imposed by the partially developed cognitive abilities and perceptual awareness of young athletes

Theophilos Pilianidis

Papers

Hormonal responses after various resistance exercise protocols.

Short-term effects of selected exercise and load in contrast training on vertical jump performance.

Failure to obtain a unique threshold on the blood lactate concentration curve during exercise

Hormonal responses after a strength endurance resistance exercise protocol in young and elderly males.

Locomotor control in the long jump approach run in young novice athletes.