Power and Explosiveness: First Step(s)

Power (along with Impulse) is arguably the most import characteristic for an athlete to develop. Power (particularly peak power) has strong relationships with sports performance such as lifting, throwing, sprinting, jumping and agility. Development of power is best accomplished by a progressive sequence that is characterized by successive phases that increased work capacity, muscle cross-section area, maximum strength and task specific power. Furthermore, evidence indicates that for power development, weaker athletes benefit as much or more from the development of strength through basic strength training than from power training

Examination of Bar Velocity in Barbell Back Squat

The aim of the study was to examine repetition to repetition changes of bar velocity and its variations from barbell back squat. Participants (N=19) performed back squat with a relative intensity of 78-80% of 1 RM. Bar velocity was captured using wireless device (PUSHtm) placed on their forearm. Data were collected from 3 sets of 10 repetitions. One-way repeated measures ANOVA was used to identify the velocity changes over 10 repetitions. Statistical significance was found (F(1,17)=45.06.~ 0 . 0 0 0 1 )T.h is indicates that the bar velocity decreased significantly over the 10 repetitions. At the same time, coefficient of variance also increased as the repetitions went higher, indicating that there were differences in individual responses of bar velocity changes. Further examination will be aimed to investigate the bar velocity changes from various strength level of individuals

Associations of Body Composition, Maximum Strength, Power Characteristics With Sprinting, Jumping, and Intermittent Endurance Performance in Male Intercollegiate Soccer Players

The purpose of this study was to determine the relationships between body composition, strength, power characteristics, sprinting, jumping, and intermittent endurance performance in collegiate male players. Twenty-three players participated (19.7 ± 1.6 yrs; 71.8 ± 7.1 kg; 176.5 ± 5.1 cm). Measurements of interest in body composition included body fat percentage (BF%), lean body mass (LBM), and body mass (BM). Power characteristics were measured with an unloaded squat jump (SJ0) and loaded SJ at 20 kg (SJ20) and 40 kg (SJ40), and unloaded countermovement jump (CMJ0). Power assessments included peak power (PP) and PP allometrically scaled (PPa). Strength characteristics were assessed using isometric mid-thigh pull. Strength assessment included isometric peak force (IPF) and IPF allometrically scaled (IPFa). Performance measures included 10m and 20 m sprint time, CMJ0 jump-height, and Yo-Yo intermittent endurance test level 1 distance. Significant correlations ranging from moderate to very large were found for LBM and CMJ jump height (CM0 JH) (p = 0.01, r = 0.50); BF% and sprint times at 10 m (p = 0.03, r = 0.44) and 20 m (p = 0.02, r = 0.50). PP and PPa from SJ0 and CMJ0 were significantly correlated to 10m sprint time (p \u3c 0.05, r = −0.45 to −0.53) and 20 m sprint time (p \u3c 0.05, r = −0.40 to −0.49). Our findings agree with previous literature in that body composition and power characteristics are directly related to soccer-related performance

Coronary heart disease risks associated with high levels of HDL cholesterol.

BackgroundThe association between high-density lipoprotein cholesterol (HDL-C) and coronary heart disease (CHD) events is not well described in individuals with very high levels of HDL-C (>80 mg/dL).Methods and resultsUsing pooled data from 6 community-based cohorts we examined CHD and total mortality risks across a broad range of HDL-C, including values in excess of 80 mg/dL. We used Cox proportional hazards models with penalized splines to assess multivariable, adjusted, sex-stratified associations of HDL-C with the hazard for CHD events and total mortality, using HDL-C 45 mg/dL and 55 mg/dL as the referent in men and women, respectively. Analyses included 11 515 men and 12 925 women yielding 307 245 person-years of follow-up. In men, the association between HDL-C and CHD events was inverse and linear across most HDL-C values; however at HDL-C values >90 mg/dL there was a plateau effect in the pattern of association. In women, the association between HDL-C and CHD events was inverse and linear across lower values of HDL-C, however at HDL-C values >75 mg/dL there were no further reductions in the hazard ratio point estimates for CHD. In unadjusted models there were increased total mortality risks in men with very high HDL-C, however mortality risks observed in participants with very high HDL-C were attenuated after adjustment for traditional risk factors.ConclusionsWe did not observe further reductions in CHD risk with HDL-C values higher than 90 mg/dL in men and 75 mg/dL in women

Force Output Comparison between Six U.S. Collegiate Athletic Teams.

The aim of the study was to compare allometrically scaled peak force and the force at 250 ms between six U.S. collegiate sport teams using isometric mid-thigh pull. Ninety subjects performed maximum effort of isometric mid-thigh pull to measure force output. The data were averaged within the teams, and statistically compared between teams using one-way ANOVA (p=.01). Significant difference was found that men’s soccer and baseball produced higher allometrically scaled peak force, and men’s soccer, tennis, and baseball produced higher allometrically scaled force at 250 ms. The data indicates that not all sports possess similar strength characteristics because of the nature of the sports, and observed separation between gender. Teams such as volleyball and baseball showed higher coefficient of variation due to the various positions within their sports

Skeletal Muscle Hypertrophy, Maximal Strength, and Rate of Force Development: Effects of Resistance Training Loading Strategy

Abstract available in the Annual Coaches and Sport Science College

Preliminary Scale of Reference Values for Evaluating Reactive Strength Index-Modified in Male and Female NCAA Division I Athletes

The purpose of this analysis was to construct a preliminary scale of reference values for reactive strength index-modified (RSImod). Countermovement jump data from 151 National Collegiate Athletic Association (NCAA) Division I collegiate athletes (male n = 76; female n = 75) were analyzed. Using percentiles, scales for both male and female samples were constructed. For further analysis, athletes were separated into four performance groups based on RSImod and comparisons of jump height (JH), and time to takeoff (TTT) were performed. RSImod values ranged from 0.208 to 0.704 and 0.135 to 0.553 in males and females, respectively. Males had greater RSImod (p \u3c 0.001, d = 1.15) and JH (p \u3c 0.001, d = 1.41) as compared to females. No statistically significant difference was observed for TTT between males and females (p = 0.909, d = 0.02). Only JH was found to be statistically different between all performance groups. For TTT no statistical differences were observed when comparing the top two and middle two groups for males and top two, bottom two, and middle two groups for females. Similarities in TTT between sexes and across performance groups suggests JH is a primary factor contributing to differences in RSImod. The results of this analysis provide practitioners with additional insight as well as a scale of reference values for evaluating RSImod scores in collegiate athletes

Injuries in Collegiate Women’s Volleyball: A Four-Year Retrospective Analysis

A four-year retrospective analysis of injury data was conducted on a collegiate (NCAA Division I) women’s volleyball team. Twenty athletes (Year 1: age = 19.4 ± 0.9 y, height = 175.2 ± 5.1 cm, body mass = 70.5 ± 10.2 kg; Year 2: age = 20.1 ± 1.0 y, height = 175.7 ± 4.7 cm, body mass = 69.5 ± 10.1 kg; Year 3: age = 20.1 ± 1.4 y, height = 173.8 ± 6.3 cm, body mass = 69.9 ± 10.8 kg; Year 4: age = 19.5 ± 1.4 y, height = 174.4 ± 8.6 cm, body mass = 72.7 ± 10.8 kg) participated in this study, accounting for 1483 total training exposures. Injury was defined as any damage to a body part, incurred during volleyball or strength and conditioning-related activities, which interfered with training and/or competition. Injury rate was normalized to the number of athletes and exposure and expressed as injuries per 1000 exposures. A total of 133 injuries were recorded. The most common injury was to the knee (left = 7.5%, right = 12.0%). Injuries occurred most often in volleyball practice (75.2%), followed by competition (20.3%), and strength and conditioning-related activities (4.5%). Non-contact injuries (upper body = 26.3%, lower body = 53.4%) were more common than contact injuries (upper-body = 13.5%, lower-body = 6.8%). An examination of injury rates relative to the training year revealed patterns in injury occurrence. Specifically, spikes in injury rate were consistently observed during periods of increased training volume that were preceded by breaks in organized training, such as the early pre-season and off-season training periods