Long-term Training Adaptations in Elite Male Volleyball Players

Abstract: Sheppard, JM, and Newton, RU. Long-term training adaptations in elite male volleyball players. J Strength Cond Res 26(8): 2180–2184, 2012—Several investigations have demonstrated differences in anthropometry, jump performance, and strength variables between developmental and elite-level volleyball players. However, within the elite level of play, the magnitude of change that can occur with training is unclear. The purpose of this investigation was to examine the anthropometric, vertical jump, and strength quality changes over 2 years in a group of national team volleyball players. Fourteen national team volleyball players (age, 23.0 ± 4.1 years; height, 1.98 ± 0.07 m; weight, 91.7 ± 7.9 kg) began and completed this study. Participants had all played international matches (representing Australia) before the examination time period and continued to do so during the international season. Anthropometry (stature, mass, and sum of 7 skinfolds), vertical jump measures (countermovement vertical jump; depth jump from 0.35 m, DJ; spike jump, SPJ, all including arm swing), and lower-body power (jump squat at body mass, and jump squat + 50% body weight, JS50) measures were tested before and at the conclusion of the investigation period. Significant (p \u3c 0.05) improvements were observed in sum of 7 skinfolds, DJ, SPJ, and JS50 performance, with large magnitude changes (d \u3e 0.70) in the sum of 7 skinfolds reduction, SPJ, and leg extensor power. This study has demonstrated that elite male volleyball players can improve leanness and power, which contribute to improvements in vertical jump

Clinical methods to quantify trunk mobility in an elite male surfing population

Background: Thoracic mobility in the sagittal and horizontal planes are key requirements in the sport of surfing; however to date the normal values of these movements have not yet been quantified in a surfing population. Objectives: To develop a reliable method to quantify thoracic mobility in the sagittal plane; to assess the reliability of an existing thoracic rotation method, and quantify thoracic mobility in an elite male surfing population. Design: Clinical Measurement, reliability and comparative study. Methods: A total of 30 subjects were used to determine the reliability component. 15 elite surfers were used as part of a comparative analysis with age and gender matched controls. Results: Intraclass correlation coefficient values ranged between 0.95-0.99 (95% CI; 0.89-0.99) for both thoracic methods. The elite surfing group had significantly (p ≤ 0.05) greater rotation than the comparative group (mean rotation 63.57° versus 40.80°, respectively). Conclusion: This study has illustrated reliable methods to assess the thoracic spine in the sagittal plane and thoracic rotation. It has also quantified ROM in a surfing cohort; identifying thoracic rotation as a key movement. This information may provide clinicians, coaches and athletic trainers with imperative information regarding the importance of maintaining adequate thoracic rotation. © 2015 Elsevier Ltd

Retrospective analysis of chronic injuries in recreational and competitive surfers:Injury location, type, and mechanism

Only two studies have reported on chronic musculoskeletal surfing injuries. They found over half of the injuries were non-musculoskeletal, but did not consider mechanisms of injury. This study identified the location, type, and mechanisms of chronic injury in Australian recreational and competitive surfers using a crosssectional retrospective observational design. A total of 1,348 participants (91.3% males, 43.1% competitive surfers) reported 1,068 chronic injuries, 883 of which were classified as major. Lower back (23.2%), shoulder (22.4%), and knee (12.1%) regions had the most chronic injuries. Competitive surfers had significantly (p \u3c .05) more lower back, ankle/foot, and head/face injuries than recreational surfers. Injuries were mostly musculoskeletal with only 7.8% being of non-musculoskeletal origin. Prolonged paddling was the highest frequency (21.1%) for mechanism of injury followed by turning maneuvers (14.8%). The study results contribute to the limited research on chronic surfing injuries

Relationships between lower-body muscle structure and, lower-body strength, explosiveness and eccentric leg stiffness in adolescent athletes

The purpose of the present study was to determine whether any relationships were present between lower-body muscle structure and, lower-body strength, variables measured during a counter-movement jump (CMJ) and squat jump (SJ), and eccentric leg stiffness, in adolescent athletes. Thirty junior male (n = 23) and female (n = 7) surfing athletes (14.8 ± 1.7 y; 1.63 ± 0.09 m; 54.8 ± 12.1 kg) undertook lower-body muscle structure assessment with ultrasonography and performed a; CMJ, SJ and an isomet-ric mid-thigh pull (IMTP). In addition, eccentric leg stiffness was calculated from variables of the CMJ and IMTP. Moderate to very large relationships (r = 0.46-0.73) were identified be-tween the thickness of the vastus lateralis (VL) and lateral gas-trocnemius (LG) muscles, and VL pennation angle and; peak force (PF) in the CMJ, SJ and IMTP. Additionally, moderate to large relationships (r = 0.37-0.59) were found between eccentric leg stiffness and; VL and LG thickness, VL pennation angle, and LG fascicle length, with a large relationship (r = 0.59) also present with IMTP PF. These results suggest that greater thick-ness of the VL and LG were related to improved maximal dy-namic and isometric strength, likely due to increased hypertro-phy of the extensor muscles. Furthermore, this increased thickness was related to greater eccentric leg stiffness, as the associated enhanced lower-body strength likely allowed for greater neuromuscular activation, and hence less compliance, during a stretch-shortening cycle

Anthropometric characteristics, upper-body strength, and sprint paddling performance in competitive surfers

The present study examined the potential differences in anthropometric characteristics, upper-body strength, and sprint paddling performance between youth and senior competitive surfers. Twenty competitive male surfers (19.1±6.8 years, 168.2±11.3 cm, 61.7±13.6 kg) were assessed for stature, mass, arm-span, ∑ 7 site skinfold thickness, Lean-Mass Ratio (LMR, ∑ 7 site skinfold/kg body-mass), pronated pull-up 1 repetition maximum (1 RM) and sprint paddling performance from a stationary start to 15 m. Independent t-tests were used to compare potential differences between youth (n:10) and senior group (n:10) of competitive surfers, with Cohen’s Effect Size (d) applied to reflect the magnitude of any differences observed. Senior surfers were not different from youth surfers for ∑ 7 site skinfold thickness, yet had greater stature (p\u3c0.001, d=2.7) and mass (p\u3c0.001, d=2.8). Consequently, the composite lean mass ratio (body-mass/∑ 7 site skinfold thickness, LMR) was greater (p=0.001, d=1.7) in senior competitive surfers. The senior surfers were faster in the 0-15 m sprint paddle test (p\u3c0.001, d=2.9), possessed higher peak paddling velocity (p\u3c0.001, d=2.3) and had greater absolute 1 RM pull-up strength (p\u3c0.001, d=2.8) and 1 RM pull-up strength relative to body-mass (1 RM pull-up mass/subjects body-mass) (p\u3c0.001, d=2.2). The results of this study suggest that practitioners working with competitive surfers should consider the importance of sprint paddle performance in surfers, and the need to optimize lean mass and relative strength, as these factors appear to distinguish between surfers of higher and lower athletic development and competitive level in the surfing population

Organic thermal maturity as a proxy for frictional fault heating: Experimental constraints on methylphenanthrene kinetics at earthquake timescales

Biomarker thermal maturity is widely used to study burial heating of sediments over millions of years. Heating over short timescales such as during earthquakes should also result in measurable increases in biomarker thermal maturity. However, the sensitivity of biomarker thermal maturity reactions to short, higher-temperature heating has not been established. We report on hydrous pyrolysis experiments that determine the kinetic parameters of methylphenanthrene maturation at timescales and temperatures relevant to earthquake heating. Samples of Woodford Shale were heated at temperatures up to 343 °C over 15–150 min. The thermal maturity of the samples as measured by the methylphenanthrene index-1 (MPI-1) increased with heating time and temperature. We find that MPI-1 increases with time and temperature consistent with a first-order kinetic model and Arrhenius temperature relationship. Over the timescales tested here, MPI-1 is strongly affected by maximum temperature and less sensitive to heating duration. Production of new phenanthrene isomers and expulsion of a liquid pyrolyzate also occurred. Differential expulsion of methylphenanthrene isomers affected the apparent maturity of the rock at lower temperatures and may need to be considered for organic-rich fault rocks. Our results demonstrate that the overall MPI-1 reaction extent in both the rock and pyrolyzate are a useful measure of thermal maturity and reflect temperature history during rapid heating

Agility literature review : Classifications, training and testing

At present, no agreement on a precise definition of agility within the sports science community exists. The term is applied to a broad range of sport contexts, but with such great inconsistency, it further complicates our understanding of what trainable components may enhance agility. A new definition of agility is proposed: "a rapid whole-body movement with change of velocity or direction in response to a stimulus". Agility has relationships with trainable physical qualities such as strength, power and technique, as well as cognitive components such as visual-scanning techniques, visual-scanning speed and anticipation. Agility testing is generally confined to tests of physical components such as change of direction speed, or cognitive components such as anticipation and pattern recognition. New tests of agility that combine physical and cognitive measures are encouraged.C