Jeremy M. Sheppard

Speed, change of direction speed, and reactive agility of rugby league players

While studies have investigated speed and change of direction speed in rugby league players, no study has investigated the reactive agility of these athletes. In addition, the relationship among speed, change of direction speed, and reactive agility within the specific context of rugby league has not been determined. With this in mind, the purpose of this study was to investigate a wide range of speed, change of direction speed, and reactive agility tests commonly used by rugby league coaches to determine which, if any tests discriminated higher and lesser skilled players, and to investigate the relationship among speed, change of direction speed, and reactive agility in these athletes. Forty-two rugby league players completed tests of speed (5 m, 10 m, and 20 m sprint), change of direction speed (‘L’ run, 505 test, and modified 505 test), and reactive agility. The validity of the tests to discriminate higher and lesser skilled competitors was evaluated by testing first grade (N = 12) and second grade (N = 30) players. First grade players had faster speed, and movement and decision times on the reactive agility test than second grade players. No significant differences were detected between first and second grade players for change of direction speed. While movement times on the reactive agility test were significantly related to 10 m and 20 m sprint times and change of direction speed, no significant relationships were detected among measures of decision time and response accuracy during the reactive agility test and measures of linear speed and change of direction speed. These findings question the validity of preplanned change of direction speed tests for discriminating higher and lesser skilled rugby league players, while also highlighting the contribution of perceptual skill to agility in these athletes.

Relative Importance of Strength, Power, and Anthropometric Measures to Jump Performance of Elite Volleyball Players

The purpose of this investigation was to examine the potential strength, power, and anthropometric contributors to vertical jump performances that are considered specific to volleyball success: the spike jump (SPJ) and counter-movement vertical jump (CMVJ). To assess the relationship among strength, power, and anthropometric variables with CMVJ and SPJ, a correlation and regression analysis was performed. In addition, a comparison of strength, power, and anthropometric differences between the seven best subjects and the seven worst athletes on the CMVJ test and SPJ test was performed. When expressed as body mass relative measures, moderate correlations (0.53-0.65; p ≤ 0.01) were observed between the 1RM measures and both relative CMVJ and relative SPJ. Very strong correlations were observed between relative (absolute height-standing reach height) depth jump performance and relative SPJ (0.85; p ≤ 0.01) and relative CMVJ (0.93; p ≤ 0.01). The single best regression model component for relative CMVJ was the relative depth jump performance, explaining 84% of performance. The single best predictor for relative SPJ was also the relative depth jump performance (72% of performance), with the three-component models of relative depth jump, relative CMVJ, spike jump contribution (percent difference between SPJ and CMVJ), and relative CMVJ, spike jump contribution, and peak force, accounting for 96% and 97%, respectively. The results of this study clearly demonstrate that in an elite population of volleyball players, stretch-shortening cycle performance and the ability to tolerate high stretch loads, as in the depth jump, is critical to performance in the jumps associated with volleyball performance.

An analysis of playing positions in elite men's volleyball: considerations for competition demands and physiologic characteristics.

Sheppard, JM Gabbett, TJ, and Reeberg Stanganelli, L-C. An analysis of playing positions in elite mens volleyball: considerations for competition demands and physiologic qualities. J Strength Cond Res 23(6): 1858-1866, 2009-The purpose of this study was to investigate the physiologic demands, physiologic characteristics, and jumping ability of different playing positions in elite male volleyball players. The first investigation involved an analysis of 16 international mens volleyball matches. The second investigation involved an analysis of the anthropometric and jump performance characteristics of 142 Development National Team (DNT) and Senior National Team (SNT) international volleyball players. Mean (±SD) frequency of block jumps for Middles (11.00 ± 3.14) was significantly greater than for Setters (6.25 ± 2.87, p < 0.001) and Outsides (6.50 ± 3.16, p < 0.001). Attack jumps were performed more frequently by Middles (7.75 ± 1.88), and this was found to be significantly more than for Setters (0.38 ± 1.06, p < 0.001) and Outsides (5.75 ± 3.25, p < 0.01). Middles were taller than Outsides and Setters (p < 0.001). Consequently, Middles had a significantly higher reach and greater body mass than Outsides (p < 0.001, p < 0.003) and Setters (p < 0.001, p < 0.001). Both Middles and Outsides had superior countermovement vertical jump (CMVJ) and spike jump (SPJ) scores compared with Setters (p < 0.001). Position-specific comparisons between DNT players and SNT players demonstrated that the SNT players were superior in relative CMVJ and SPJ scores (p < 0.05), with a large magnitude of effect (d > 0.99). The results of this study highlight the large jumping and landing demands placed on the taller and heavier players in the middle position. In addition to establishing the magnitude of difference in jumping ability between junior and senior national team players, the results also provide a comprehensive data set that may assist with talent identification and talent development for aspiring male volleyball players.

Contribution of strength characteristics to change of direction and agility performance in female basketball athletes.

Abstract Spiteri, T, Nimphius, S, Hart, NH, Specos, C, Sheppard, JM, and Newton, RU. Contribution of strength characteristics to change of direction and agility performance in female basketball athletes. J Strength Cond Res 28(9): 2415–2423, 2014—Research has often examined the relationship between 1 or 2 measures of strength and change of direction (COD) ability reporting inconsistent relationships to performance. These inconsistencies may be the result of the strength assessment used and the assumption that 1 measure of strength can represent all “types” of strength required during a COD task. Therefore the purpose of this study was to determine the relationship between several lower-body strength and power measures, COD, and agility performance. Twelve (n = 12) elite female basketball athletes completed a maximal dynamic back squat, isometric midthigh pull, eccentric and concentric only back squat, and a countermovement jump, followed by 2 COD tests (505 and T-test) and a reactive agility test. Pearson product-moment correlation and stepwise regression analysis were performed on all variables. The percentage contribution of each strength measure to an athletes total strength score was also determined. Our results demonstrated that both COD tests were significantly correlated to maximal dynamic, isometric, concentric, and eccentric strength (r = −0.79 to −0.89), with eccentric strength identified as the sole predictor of COD performance. Agility performance did not correlate with any measure of strength (r = −0.08 to −0.36), whereas lower-body power demonstrated no correlation to either agility or COD performance (r = −0.19 to −0.46). These findings demonstrate the importance of multiple strength components for COD ability, highlighting eccentric strength as a deterministic factor of COD performance. Coaches should aim to develop a well-rounded strength base in athletes; ensuring eccentric strength is developed as effectively as the often-emphasized concentric or overall dynamic strength capacity.

Understanding position transducer technology for strength and conditioning practitioners

STRENGTH AND POWER ASSESSMENTS IN CONDITIONING PRACTICE HAVE TYPICALLY INVOLVED RUDIMENTARY MEASURES SUCH AS 1 REPETITION MAXIMUM. MORE COMPLEX LABORATORY ANALYSIS HAS BEEN AVAILABLE BUT BECAUSE OF THE PRICE AND PORTABILITY OF EQUIPMENT, SUCH ANALYSIS REMAINED IMPRACTICAL TO MOST PRACTITIONERS. RECENTLY, A NUMBER OF DEVICES HAVE BECOME AVAILABLE THAT ARE REASONABLY INEXPENSIVE AND PORTABLE AND OFFER A GREAT DEAL OF INFORMATION THAT CAN BE USED TO GUIDE PROGRAMMING AND TRAINING TO BETTER EFFECT. ONE SUCH DEVICE IS THE LINEAR POSITION TRANSDUCER. THIS ARTICLE DISCUSSES THIS PIECE OF TECHNOLOGY FROM ITS DESIGN TO HOW IT MAY BE USED TO INFORM PRACTICE.

The Effect of Assisted Jumping on Vertical Jump Height in High-Performance Volleyball Players

Assisted jumping may be useful in training higher concentric movement speed in jumping, thereby potentially increasing the jumping abilities of athletes. The purpose of this study was to evaluate the effects of assisted jump training on counter-movement vertical jump (CMVJ) and spike jump (SPJ) ability in a group of elite male volleyball players. Seven junior national team volleyball players (18.0±1.0 yrs, 200.4±6.7 cm, and 84.0±7.2 kg) participated in this within-subjects cross-over counter-balanced training study. Assisted training involved 3 sessions per week of CMVJ training with 10 kg of assistance, applied through use of a bungee system, whilst normal jump training involved equated volume of unassisted counter-movement vertical jumps. Training periods were 5 weeks duration, with a 3-week wash-out separating them. Prior to and at the conclusion of each training period jump testing for CMVJ and SPJ height was conducted. Assisted jump training resulted in gains of 2.7±0.7 cm (p<0.01, ES=0.21) and 4.6±2.6 cm (p<0.01, ES=0.32) for the CMVJ and SPJ respectively, whilst normal jump training did not result in significant gains for either CMVJ or SPJ (p=0.09 and p=0.51 respectively). The changes associated with normal jump training and assisted jump training revealed significant differences in both CMVJ and SPJ (p=<0.03) in favour of the assisted jump condition, with large effect (CMVJ, ES=1.22; SPJ, ES=1.31). Assisted jumping may promote the leg extensor musculature to undergo a more rapid rate of shortening, and chronic exposure appears to improve jumping ability.

Mechanical Determinants of Faster Change of Direction and Agility Performance in Female Basketball Athletes.

Abstract Spiteri, T, Newton, RU, Binetti, M, Hart, NH, Sheppard, JM, and Nimphius, S. Mechanical determinants of faster change of direction and agility performance in female basketball athletes. J Strength Cond Res 29(8): 2205–2214, 2015—Change of direction (COD) and agility require the integration of multiple components to produce a faster performance. However, the mechanisms contributing to a faster performance without the confounding factor of athlete expertise or gender is currently unknown. Therefore, the purpose of this study was to assess body composition, strength, and kinetic profile required for a faster COD and agility performance across multiple directional changes. Six faster and 6 slower (n = 12) elite female basketball athletes completed a maximal dynamic back squat; eccentric and concentric only back squat; isometric midthigh pull; whole-body scan to determine lean, fat, and total mass; 505 COD test; T-test; and a multidirectional agility test over in-ground force plates to obtain relevant kinetic measures. Group (faster and slower) by test (2 × 3) multivariate analyses of variance with follow-up analyses of variance were conducted to examine differences between faster and slower groups and each COD and agility test (p ⩽ 0.05). Faster athletes during the 505 COD test produced significantly greater vertical force (p = 0.002) and eccentric and isometric strength capacity (p = 0.001). Faster agility and T-test athletes demonstrated significantly shorter contact times (p = 0.001), greater propulsive impulse (p = 0.02), isometric strength, and relative lean mass compared with slower athletes. Differences between faster athletes across each test seem to be attributed to the mechanical demands of the directional change, increasing force and impulse application as the degree of directional change increased. These findings indicate that different mechanical properties are required to produce a faster COD and agility performances, and the importance of a greater strength capacity to enable greater mechanical adjustment through force production and body control, during different directional changes.

Influence of closed skill and open skill warm-ups on the performance of speed, change of direction speed, vertical jump, and reactive agility in team sport athletes.

Gabbett, TJ, Sheppard, JM, Pritchard-Peschek, KR, Leveritt, MD, and Aldred, MJ. Influence of closed skill and open skill warm-ups on the performance of speed, change of direction speed, vertical jump, and reactive agility in team sports athletes. J Strength Cond Res 22(5): 1413-1415, 2008-In this study, we evaluated the efficacy of two different dynamic warm-up conditions, one that was inclusive of open skills (i.e., reactive movements) and one that included only preplanned dynamic activities (i.e., closed skills) on the performance of speed, change of direction speed, vertical jump, and reactive agility in team sport athletes. Fourteen (six male, eight female) junior (mean ± SD age, 16.3 ± 0.7 year) basketball players participated in this study. Testing was conducted on 2 separate days using a within-subjects cross-over study design. Each athlete performed a standardized 7-minute warm-up consisting of general dynamic movements and stretching. After the general warm-up, athletes were randomly allocated into one of two groups that performed a dynamic 15-minute warm-up consisting entirely of open or closed skills. Each of the warm-up conditions consisted of five activities of 3 minute duration. At the completion of the warm-up protocol, players completed assessments of reactive agility, speed (5-, 10-, and 20-m sprints), change of direction speed (T-test), and vertical jump. No significant differences (p > 0.05) were detected among warm-up conditions for speed, vertical jump, change of direction speed, and reactive agility performances. The results of this study demonstrate that either open skill or closed skill warm-ups can be used effectively for team sport athletes without compromising performance on open skill and closed skill tasks.

Association Between Anthropometry and Upper-Body Strength Qualities With Sprint Paddling Performance in Competitive Wave Surfers

Abstract Sheppard, JM, McNamara, P, Osborne, M, Andrews, M, Oliveira Borges, T, Walshe, P, and Chapman, DW. Association between anthropometry and upper-body strength qualities with sprint paddling performance in competitive wave surfers. J Strength Cond Res 26(12): 3345–3348, 2012—This study aimed to evaluate the potential association with anthropometry and upper-body pulling strength with sprint kinematics of competitive surfers. Ten competitive male surfers (23.9 ± 6.8 years, 177.0 ± 6.5 cm, 72.2 ± 2.4 kg) were assessed for stature, mass, arm span, ∑ 7 site skinfold thickness, pronated pull-up strength, and sprint paddling performance from a stationary start to 15 m. Pearson correlation analysis, and independent t-tests were used to compare potential differences between the slower and faster group of sprint paddlers. Strong associations were found between relative (total kilograms lifted per athlete mass) upper-body pulling strength and sprint paddling time to 5, 10, and 15 m, and peak sprint paddling velocity (r = 0.94, 0.93, 0.88, 0.66, respectively, p < 0.05) and relative upper-body pulling strength was found to be superior (p < 0.05) in the faster group, with large effect (d = 1.88). The results of this study demonstrate a strong association between relative upper-body pulling strength and sprint paddling ability in surfers. Strength and conditioning coaches working with competitive surfers should implement strength training with surfers, including an emphasis on developing relative strength, because this may have a strong influence on sprint paddling performance.

Long-term training-induced changes in sprinting speed and sprint momentum in elite rugby union players

Abstract Barr, MJ, Sheppard, JM, Gabbett, TJ, and Newton, RU. Long-term training-induced changes in sprinting speed and sprint momentum in elite rugby union players. J Strength Cond Res 28(10): 2724–2731, 2014—Speed and sprint momentum are considered to be important physical qualities for rugby. The purpose of the study was to understand the development of these qualities in senior and junior international rugby players. In part 1 of the study, a group of senior (n = 38) and junior (n = 31) players were tested for speed over 40 m. Initial sprint velocity (ISV), maximal sprint velocity (MSV), initial sprint momentum (ISM), and maximal sprint momentum (MSM) were calculated using 10-m splits. In part 2 of the study, a group of junior (n = 12) and senior (n = 15) players were tracked over a 2-year period for body mass, ISV, MSV, ISM, and MSM. In part 1, senior backs and forwards were not found to have significantly greater ISV and MSV than junior players but were found to have greater ISM and MSM. Forwards were found to have significantly greater ISM and MSM than backs but significantly lower ISV and MSV than backs. In part 2, no significant differences were found over the 2 years between senior and junior players, but greater effect sizes for juniors were generally found when compared with seniors for improvements in ISV (d = 0.73 vs. 0.79), MSV (d = 1.09 vs. 0.68), ISM (d = 0.96 vs. 0.54), and MSM (d = 1.15 vs. 0.50). Sprint momentum is a key discriminator between senior and junior players, and large changes can be made by junior players as they transition into senior rugby. Speed appears to peak for players in their early 20s but sprint momentum appears to be more trainable.