Showing papers by "Geoffrey M. Minett published in 2017"

The Specificity of Rugby Union Training Sessions in Preparation for Match Demands.

Abstract: Purpose Investigations into the specificity of rugby union training practices in preparation for competitive demands has predominantly focussed on physical and physiological demands. The evaluation of the contextual variance in perceptual strain or skill requirements between training and matches in rugby union is unclear, yet holistic understanding may assist to optimise training design. This study evaluated the specificity of physical, physiological, perceptual and skill demands of training sessions compared with competitive match-play in pre-professional, elite club rugby union. Methods Global positioning system (GPS) devices, video capture, heart rate (HR), and session ratings of perceived exertion (sRPE) were used to assess movement patterns, skill completions, physiologic, and perceptual responses, respectively. Data were collected across a season (training sessions n=29; matches n=14). Participants (n=32) were grouped in playing positions as: outside backs, centres, halves, loose forwards, lock forwards, and front row forwards. Results Greater total distance, low-intensity activity, maximal speed and metres per min were apparent in matches compared to training in all positions (P 0.90). Similarly, match HR, and sRPE responses were higher than those recorded in training (P 0.8). Key skill completions for forwards (i.e., scrums, rucks and lineouts) and backs (i.e., kicks) were greater under match conditions than in training (P 1.50). Conclusion Considerable disparities exist between the perceptual, physiological, and key skill demands of competitive matches versus training sessions in pre-professional rugby union players. Practitioners should consider the specificity of training tasks for pre-professional rugby players to ensure the best preparation for match demands.

Core temperature responses to Cold-Water immersion recovery: A Pooled-Data Analysis

Abstract: Purpose To examine the effect of post-exercise cold water immersion (CWI) protocols compared with control (CON), on the magnitude and time-course of core temperature (Tc) responses. Methods Pooled data analyses were used to examine the Tc responses of 157 subjects from previous post-exercise CWI trials in our laboratories. CWI protocols varied with different combinations of temperature, duration, immersion depth and mode (continuous vs intermittent). Tc was examined as a double difference (ΔΔTc), calculated as the change in Tc in CWI condition minus the corresponding change in CON. The effect of CWI on ΔΔTc was assessed using separate linear mixed models across two time components (Component 1: immersion, and Component 2: post-intervention). Results Intermittent CWI resulted in a mean decrease in ΔΔTc that was 0.254±0.10°C (estimate ± SE) greater than continuous CWI during the immersion component (P=0.022). There was a significant effect of CWI temperature during the immersion component (P=0.050), where reductions in water temperature of 1°C resulted in decreases in ΔΔTc of 0.03±0.01°C. Similarly, the effect of CWI duration was significant during the immersion component (P=0.01), where every 1 min of immersion resulted in a decrease in ΔΔTc of 0.02±0.01°C. The peak difference in Tc between the CWI and CON interventions during the post-immersion component occurred at 60 min post-intervention. Conclusion Variations in CWI mode, duration and temperature, may have a significant effect on the extent of change in Tc. Careful consideration should be given to determine the optimal amount of core cooling before deciding which combination of protocol factors to prescribe.

Drop punt kicking induces eccentric knee flexor weakness associated with reductions in hamstring electromyographic activity

Abstract: Objectives - To examine the effect of 100 drop punt kicks on isokinetic knee flexor strength and surface electromyographic (sEMG) activity of bicep femoris (BF) and medial hamstrings (MH) Design - Randomised control study Methods - Thirty-six recreational footballers were randomly assigned to kicking or control groups Dynamometry was conducted immediately before and after the kicking or 10 minutes of sitting (control) Results - Eccentric strength declined more in the kicking than the control group (p < 0001; d = 160), with greater reductions in eccentric than concentric strength after kicking (p = 0001; d = 092) No significant between group differences in concentric strength change were observed (p = 0089; d = 060) The decline in normalized eccentric hamstring sEMG (BF and MH combined) was greater in the kicking than the control group (p < 0001; d =178), while changes in concentric hamstring sEMG did not differ between groups (p = 0863; d = 004) Post-kicking reductions in sEMG were greater in eccentric than concentric actions for both BF (p = 0008; d = 077) and MH (p < 0001; d = 111) In contrast, the control group exhibited smaller reductions in eccentric than concentric hamstring sEMG for BF (p = 0026; d = 064) and MH (p = 0032; d = 053) Reductions in BF sEMG were correlated with eccentric strength decline (R = 0645; p = 0007) Conclusions - Reductions in knee flexor strength and hamstring sEMG are largely limited to eccentric contractions and this should be considered when planning training loads in Australian Football