Thomas M. Comyns

THE OPTIMAL COMPLEX TRAINING REST INTERVAL FOR ATHLETES FROM ANAEROBIC SPORTS

Comyns, T.M., A.J. Harrison, L.K. Hennessy, and R.L. Jensen. The optimal complex training rest interval for ath- letes from anaerobic sports. J. Strength Cond. Res. 20(3):471- 476. 2006.—Complex training research has indicated that 3-4 minutes may be an optimum intracomplex rest interval. The purpose of this study was to determine if a heavy resistive ex- ercise causes performance enhancement of a slow stretch-short- ening cycle exercise and if there is an optimal rest interval. Eighteen subjects performed countermovement jumps (CMJs) before and after a 5 repetition maximum back squat lifting pro- tocol. This procedure was repeated 4 times over 2 days using rest intervals of 30 seconds and 2, 4, and 6 minutes. Flight time and peak ground reaction force (GRF) were the dependent var- iables. All jumps were performed on a specially constructed sledge and force platform apparatus. Repeated measures anal- ysis of variance found a significant reduction in flight time at the 30-second and 6-minute interval (p 0.05). No significant difference was found between men and women. Only the men showed an enhancement in jump performance after the 4-min- ute interval. The improvement window was different for each subject, and an analysis of the greatest increase and decrease in flight time and peak GRF was conducted, showing a significant decrease for men and women and a significant increase in flight time for men and peak ground reaction force for women. The results suggest that complex training can benefit or inhibit CMJ performance depending on the rest interval. The individual de- termination of the intracomplex rest interval may be necessary in the practical setting.

Identifying the optimal resistive load for complex training in male rugby players

Alternating a resistance exercise with a plyometric exercise is referred to as “complex training”. In this study, we examined the effect of various resistive loads on the biomechanics of performance of a fast stretch–shortening cycle activity to determine if an optimal resistive load exists for complex training. Twelve elite rugby players performed three drop jumps before and after three back squat resistive loads of 65%, 80%, and 93% of a single repetition maximum (1-RM) load. All drop jumps were performed on a specially constructed sledge and force platform apparatus. Flight time, ground contact time, peak ground reaction force, reactive strength index, and leg stiffness were the dependent variables. Repeated-measures analysis of variance found that all resistive loads reduced (P < 0.01) flight time, and that lifting at the 93% load resulted in an improvement (P < 0.05) in ground contact time and leg stiffness. From a training perspective, the results indicate that the heavy lifting will encourage the fast stretch–shortening cycle activity to be performed with a stiffer leg spring action, which in turn may benefit performance. However, it is unknown if these acute changes will produce any long-term adaptations to muscle function.

EFFECT OF SQUATTING ON SPRINTING PERFORMANCE AND REPEATED EXPOSURE TO COMPLEX TRAINING IN MALE RUGBY PLAYERS

Comyns, TM, Harrison, AJ, and Hennessy, LK. Effect of squatting on sprinting performance and repeated exposure to complex training in male rugby players. J Strength Cond Res 24(3): 610-618, 2010-This study was undertaken to examine the effect of a heavy weight training exercise on sprinting performance and on the effect of repeated exposure to a complex training protocol. Eleven male rugby union players (age 20.9 ± 3.1 years) participated in the study, which involved 5 separate testing sessions. Back squat 3 repetition maximum (3RM) was established in session 1. Sessions 2-5 were identical and involved the subjects completing a 30-m sprint before and after a 3RM back squat protocol. Four minutes of rest was given between the back squatting and the posttest 30-m sprint. All sprint trials were measured with a laser measurement device (LAVEG, Jenoptik, Jena, Germany). Sprint time and instantaneous, average, and maximum velocity were the dependent variables. The criterion for significance was set at an alpha level of p ≥ 0.05. No significant improvement was evident for any of the testing sessions (p ≥ 0.05). In session 1, there was a significant increase in 30-m time and a significant reduction in average 30-m velocity and maximum velocity (p < 0.05). The expected benefits in sprinting may not have been realized because of intra and intersubject variations in sprint technique. The session × phase interaction revealed a significant improvement in the pre to posttest changes in instantaneous velocity at 20 m (p = 0.035) and 30 m (p = 0.036) from session 1 to session 4. This indicates that the rugby players may be able to learn to apply the potentiation effects of complex training. From a practical perspective, players may need repeated exposure to this training modality to gain benefit from it, and this should be reflected in program planning.

Validation of an electronic jump mat to assess stretch-shortening cycle function

Abstract Kenny, IC, Ó Cairealláin, A, and Comyns, TM. Validation of an electronic jump mat to assess stretch-shortening cycle function. J Strength Cond Res 26(6): 1601–1608, 2012—The purpose of this investigation was to determine the concurrent validity of a commonly used electronic switch mat (ESM), or jump mat, compared with force plate (FP) data. The efficiency of collection and accuracy of data are paramount to athlete and player field testing for the strength and conditioning coach who often has access only to a jump mat. Ten subjects from 5 different sporting backgrounds completed 3 squat jumps (SJs), 3 countermovement jumps (CMJs), and 3 drop jumps (DJs). The jumps were performed on an AMTI FP operating at 1,000 Hz with an ESM positioned on top of the platform. All the subjects were experienced with the protocols involved with jump testing. The resulting absolute errors between FP and ESM data were 0.01, 0.02, and 0.01 m for CMJ, SJ, and DJ heights, respectively. However, the coefficient of variation for the DJ contact time (CT) was 57.25%, CMJ (r = 0.996), and SJ (r = 0.958) heights correlated very strongly with force platform data, and DJ data were not as strong (r = 0.683). Confidence interval tests revealed bias toward CMJ and SJ (p < 0.05). The jump mat can accurately calculate the CMJ height, SJ height, and reactive strength index for all the 3 jump protocols. However, the faster CTs and rapid movements involved in a DJ may limit its reliability when giving measures of CT, flight time, and height jumped for DJs. Strength and conditioning coaches can use such a jump mat device with the confidence that it is accurately producing valid measurements of their athletes performance for CMJ and SJ slow SSC protocols.

An investigation into the recovery process of a maximum stretch-shortening cycle fatigue protocol on drop and rebound jumps

Comyns, TM, Harrison, AJ, and Hennessy, LK. An investigation into the recovery process of a maximum stretch-shortening cycle fatigue protocol on drop and rebound jumps. J Strength Cond Res 25(8): 2177-2184, 2011—The aim of this study was to investigate the recovery process of a maximal stretch-shortening cycle (SSC) fatigue workout on the biomechanical performance of drop jump (DJ) and rebound jump (RBJ) on a force sledge apparatus. Thirteen elite level rugby players performed sledge DJs and RBJs before and 15, 45, 120, and 300 seconds after a maximum SSC fatigue workout. Flight time, ground contact time (CT), peak force, reactive strength index (RSI), and leg-spring stiffness were the dependent variables. The DJ results showed that after 15 seconds recovery, there was a significant reduction in flight time (FT) (p < 0.01), RSI (p < 0.001), peak force (p < 0.01), and leg stiffness (p < 0.001). Similarly, the results for the RBJ indicated that the fatigue workout significantly reduced FT (p < 0.001), peak force (p < 0.01), RSI (p < 0.01), and significantly increased CT (p < 0.05) at the 15-second interval. The results also indicated a potentiation effect at the 300-second interval because of significant increases in RSI, peak force, and leg stiffness (p < 0.05) for the RBJ and significant increases in RSI (p < 0.05), peak force, and leg stiffness (p < 0.01) and a significant decrease in ground CT (p < 0.05) for the DJ. A maximal SSC fatigue workout had both an inhibiting and potentiating effect on DJ and RBJ performance depending on the recovery interval. The efficiency of the SSC function was reduced immediately after the cessation of the fatigue workout. A potentiation effect was evident for both jumps 300 seconds postfatigue.

Effects of a Low-Load Gluteal Warm-Up on Explosive Jump Performance

Abstract The purpose of this study was to investigate the effects of a low-load gluteal warm-up protocol on countermovement and squat jump performance. Research by Crow et al. (2012) found that a low-load gluteal warm-up could be effective in enhancing peak power output during a countermovement jump. Eleven subjects performed countermovement and squat jumps before and after the gluteal warm-up protocol. Both jumps were examined in separate testing sessions and performed 30 seconds, and 2, 4, 6 & 8 minutes post warm-up. Height jumped and peak ground reaction force were the dependent variables examined in both jumps, with 6 additional variables related to fast force production being examined in the squat jump only. All jumps were performed on a force platform (AMTI OR6-5). Repeated measures analysis of variance found a number of significant differences (p ≤ 0.05) between baseline and post warm-up scores. Height jumped decreased significantly in both jumps at all rest intervals excluding 8 minutes. Improvement was seen in 7 of the 8 recorded SJ variables at the 8 minute interval. Five of these improvements were deemed statistically significant, namely time to peak GRF (43.0%), and time to the maximum rate of force development (65.7%) significantly decreased, while starting strength (63.4%), change of force in first 100 ms of contraction (49.1%) and speed strength (43.6%) significantly increased. The results indicate that a gluteal warm-up can enhance force production in squat jumps performed after 8 minutes recovery. Future research in this area should include additional warm-up intervention groups for comparative reasons.

Performance effects of repetition specific gluteal activation protocols on acceleration in male rugby union players

Abstract Warm-up protocols have the potential to cause an acute enhancement of dynamic sprinting performance. The purpose of this study was to evaluate the effects of three repetition specific gluteal activation warm-up protocols on acceleration performance in male rugby union players. Forty male academy rugby union players were randomly assigned to one of 4 groups (control, 5, 10 or 15 repetition gluteal activation group) and performed 10 m sprints at baseline and 30 s, 2, 4, 6 and 8 min after their specific intervention protocol. Five and ten meter sprint times were the dependent variable and dual-beam timing gates were used to record all sprint times. Repeated measures analysis of variance found no significant improvement in 5 and 10 m sprint times between baseline and post warm-up scores (p ≥ 0.05) for all groups. There were no reported significant differences between groups at any of the rest interval time points (p ≥ 0.05). However, when individual responses to the warm-up protocols were analyzed, the 15 repetition gluteal activation group had faster 10 m times post-intervention and this improvement was significant (p = 0.021). These results would indicate that there is no specific rest interval for any of the gluteal interventions that results in a potentiation effect on acceleration performance. However, the individual response analysis would seem to indicate that a 15 repetition gluteal activation warm-up protocol has a potentiating effect on acceleration performance provided that the rest interval is adequately and individually determined.

The Incidence of Injury in Amateur Male Rugby Union: A Systematic Review and Meta-Analysis

BackgroundRugby union is a physically demanding, full-contact team sport that has gained worldwide popularity. The incidence of injury in rugby union has been widely reported in the literature. While comprehensive injury surveillance and prevention programmes have been implemented within the professional game, there is a need for similar strategies in the amateur game. Despite recent increases in the volume of research in rugby, there is little consensus regarding the true incidence rate of match and training injuries in senior amateur male rugby union players.ObjectiveThe aim of the current review was to systematically review the available evidence on the epidemiology of time-loss injuries in senior amateur male rugby union players and to subsequently conduct a meta-analysis of the findings.MethodsA comprehensive search of the PubMed, Scopus, SportDiscus and Google Scholar electronic databases was performed using the following keywords; (‘rugby’ OR ‘rugby union’) AND (‘amateur’ OR ‘community’) AND (‘injur*’ OR ‘pain*’). Six articles regarding the incidence of injury in senior amateur male rugby union players, in both matches and training, were retrieved and included in the meta-analysis to determine the overall incidence rate of match injury, with descriptive analyses also provided for other reported variables.ResultsThe overall incidence rate of match injuries within senior amateur rugby union players was 46.8/1000 player hours [95% confidence interval (CI) 34.4–59.2]. Contact events accounted for the majority of injuries, with the tackler more at risk than the player being tackled, and with respective incidence rates of 15.9/1000 player hours (95% CI 12.4–19.5) and 12.2/1000 player hours (95% CI 9.3–15.1).ConclusionThis meta-analysis found that the incidence rate of injury in amateur rugby union players was lower than that in professional players, but higher than the incidences reported in adolescent and youth rugby players. By understanding the true incidence and nature of injuries in rugby, injury prevention strategies can best be implemented. Future prevention strategies may best be aimed towards the tackle area, specifically to the tackler, in order to minimize injury risk.

The associations between training load and baseline characteristics on musculoskeletal injury and pain in endurance sport populations: A systematic review

OBJECTIVES To determine the associations between training load, baseline characteristics (e.g. age or previous injury) and rate of musculoskeletal injury and/or pain specifically within an Endurance Sporting Population (ESP). DESIGN Prospectively registered systematic review. METHODS Eight electronic databases were searched by two independent reviewers. Studies were required to prospectively monitor both (i) training loads and (ii) musculoskeletal injury and/or pain for >3 months. Methodological quality and risk of bias were determined utilising the Critical Skills Appraisal Program (CASP). Reported effect sizes were categorised as small, medium or large. RESULTS Twelve endurance sport studies were eligible (running, triathlon, rowing). Increased injury and/or pain risk was associated with: (i) high total training distances per week/month (medium effect size) (ii) training frequency <2 sessions/week (medium effect size) and (iii) both low weekly (<2hours/week) and high monthly (large effect size) training durations. None of the studies reported internal training load data or acute:chronic workload ratios. Baseline characteristics found to increase the rate of injury and/or pain included: (i) a history of previous injury (medium effect size), (ii) age >45 years (small effect size), (iii) non-musculoskeletal comorbidities (large effect size), (iv) using older running shoes (small effect size) and (v) non-competitive behaviour. CONCLUSIONS This review identifies a range of external training load factors and baseline characteristics associated with an increased rate of injury and/or pain within ESPs. There is an absence of research relating to internal training loads and acute:chronic workload ratios in relation to rate of injury and/or pain within ESPs.

The Application of Postactivation Potentiation Methods to Improve Sprint Speed

THIS ARTICLE EXAMINES THE APPLICATION OF A VARIETY OF MODALITIES TO ELICIT A POSTACTIVATION POTENTIATION (PAP) RESPONSE IN SPRINTING. WE PRESENT THE EXISTING LITERATURE ON THE ACUTE EFFECTS OF BACK SQUATS, POWER CLEANS, PLYOMETRICS, AND SLED PULLING ON SPRINT DISTANCES RANGING FROM 5 TO 50 M. WE ALSO DISCUSS AND PROVIDE AN EXAMPLE OF HOWCOACHESCAN ASSESS THE INDIVIDUAL EFFECTS OF PAP PROTOCOLS ON THEIR ATHLETES TO IDENTIFY WHETHER A PROTOCOL ELICITS AN ACUTE IMPROVEMENT OR IMPAIRMENT IN PERFORMANCE. FINALLY, WE PROVIDE PRACTICAL RECOMMENDATIONS ON HOW COACHES CAN INCORPORATE THESE METHODS INTO A SPRINT TRAINING SESSION.