MEASURING BILATERAL ASYMMETRY IN A LONGTERM ATHLETE MONITORING

The purpose of this lecture is to provide examples of how biomechanical testing methods are used to analyse bilateral asymmetry from a longterm athlete monitoring program. This lecture includes the results of bilateral asymmetry data to examine the physical status of both highly competitive and recreational athletes. Athlete monitoring is a vital component of achieving a successful athletic career. It is important to understand how the magnitude of bilateral asymmetry is potentially detrimental to performance. The bilateral asymmetry data has been analysed to understand physical demands of athletes in various sports. Different types of jumping, landing, and isometric tests have provided data showing effectiveness of the tests in displaying the athlete’s physical characteristics. Bridging the gap between science and practice is mentioned in the lecture

VERTICAL JUMP PERFORMANCE DURING VIDEO SIMULATED BLOCKING AND MAXIMAL EFFORT JUMPING IN FEMALE COLLEGIATE VOLLEYBALL PLAYERS

This study’s purpose was to compare jump height, velocity and force production between video simulated blocking, [reactive timing (RT) jump], and maximal effort vertical jumping, [self-select timing (SST) jump]. 10 female collegiate volleyball players performed both jumps onto a force plate in a laboratory while being videotaped with one camera. Jump heights(cm), velocities(m/s), and forces(%BW) were calculated using Peak Motus. A RMMANOVA identified differences in the dependent variables across the two jumps. Jump height and peak velocity were significantly higher in the SST jump, 52.20+8.43 v 38.33+11.76 cm, and 5.69+0.71 v 5.4+0.61 m/s, respectively,

Does core strength training influence kinetic efficiency, lower extremity stability, and 5000m performance in runners?

Context: Core strength training (CST) has been popular in the fitness industry for a decade. Although strong core muscles are believed to enhance athletic performance, only few scientific studies have been conducted to identify the effectiveness of CST on improving athletic performance. Objective: Identify the effects of a 6-wk CST on running kinetics, lower extremity stability, and running performance in recreational and competitive runners. Design and Setting: A test-retest, randomized control design was used to assess the effect of CST and no CST on ground reaction force (GRF), lower extremity stability scores, and running performance. Participants: Twenty-eight healthy adults (age, 36.9+9.4yrs, height, 168.4+9.6cm, mass, 70.1+15.3kg) were recruited and randomly divided into two groups. Main outcome Measures: GRF was determined by calculating peak impact vertical GRF (vGRF), peak active vGRF, duration of the breaking or horizontal GRF (hGRF), and duration of the propulsive hGRF as measured while running across a force plate. Lower extremity stability in three directions (anterior, posterior, lateral) was assessed using the Star Excursion Balance Test (SEBT). Running performance was determined by 5000 meter run measured on selected outdoor tracks. Six 2 (time) X 2 (condition) mixed-design ANOVA were used to determine if CST influences on each dependent variable, p \u3c .05. Results: No significant interactions were found for any kinetic variables and SEBT score, p\u3e.05. But 5000m run time showed significant interaction, p \u3c .05. SEBT scores improved in both groups, but more in the experimental group. Conclusion: CST did not significantly influence kinetic efficiency and lower extremity stability, but did influence running performance

Investigation into Characteristics of Bench Press using PUSH Band

Introduction: Sport scientist and strength coaches use resistance training to increase athletic performance and muscle hypertrophy. Improving muscular strength is the most essential task for these scientists, however, how best to identify weakness has yet to be established. The popularity of velocity-based resistance training has recently increased as a method to prescribe resistance training intensity, therefore, the purpose of the study was to identify the characteristics of bench press concentric velocity. It is hypothesized that the velocity output will decrease during the change from the 75% relative load of the 1RM to the 85% relative load of 1RM. It is believed that there will be a greater output of velocity during the 75% set than the 85% set. Methods: Nine female collegiate athletes (18-21 yrs), participated in this study. PUSH™ bands were used to measure barbell velocity during the bench press exercise. Each female was expected to preform 3 sets of 5 repetitions (3x5) at an intensity of 75% and 85% of their 1 repetition maximum (1RM). Only data from repetition 2-4 were used for analysis. Results: The results drawn from data collected supported our hypothesis showing a decrease in velocity among the 85% 1RM test when compared to the 75% 1RM test group. Comparisons were drawn using a t-Test table comprised of PUSH™ Band data. Conclusion: The results supported the hypothesis that this type of technology can identify the load specific velocity to help strength coaches to identify the optimal resistance for certain training program and goals by using collected data with the PUSH™ Band to identify weakness in strength and/or endurance

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

RELATIONSHIP BETWEEN GROUND REACTION FORCE AND STABILITY LEVEL OF THE LOWER EXTREMITY IN YOUNG ACTIVE ADULTS

The purpose of this study was to identify the relationship between GRF and the stability level of the lower extremity to define the risk of running-related injuries. 13 participants were divided to two groups (previous running injury; no previous running injury) and performed a Single-leg Excursion Test (SET), and ran across a force plate to measure GRFs. Results showed a moderate negative correlation, (r(10) =-0.620, P < 0.05). The injury group had higher GRF and lower SET scores as compared to the no injury group. Runners that can reduce the GRF and improve their stability level in the 'lower extremity by performing proper strength and stability training may reduce the risk of injuries from running activities

Differences in Closed-Loop Control of Cutting Movements Between Collegiate Athletes and Non-Athletes

Background: The ability of athletes to make quick adaptations or adjustments in their movement is based on the closed-loop control system. One area of interest in athletic performance is the ability for athletes to perform cutting movements in unpredictable environments. Objective: To determine the interactions of two groups of participants and cutting angles in vertical ground reaction forces (GRFs) and time of foot contact in a closed-loop environment. The study also compared the two given time-frames to process feedback between athletes and non-athletes. Design and Setting: Measurements of the time of foot contact and the active vertical GRF were recorded to compare the movement efficiency. Collegiate athletes and healthy young adults were used for base samples. Subjects: Ten participants (5 collegiate soccer players and 5 healthy young adults) volunteered. Measurements: The time of foot contact and the active vertical GRF were measured in a total of 8 trials in 4 different angles and two different time-frame conditions. Data were analyzed using two 2*4 mixed-design ANOVA, p&lt; 0.05. Results: The athletes performed higher active vertical GRF in the shorter time of foot contact, compared to the non-athletes. The results did not show significant interaction

COMPARISON IN FORCE GENERATION AND TIME OF FOOT CONTACT IN FOUR DIFFERENT CUTTING ANGLES BETWEEN ATHLETES AND NON-ATHLETES

The purpose of this study was to determine the differences in peak active vertical ground reaction force (vGRF) and time of foot contact in four different cutting angles of a closed-loop situation between two groups. A total of 10 participants (n=5, athletes, n=5, non-athletes) ran across a force plate to measure peak active vGRF and time of foot contact in four different angles. Data were analyzed using two 2x4 mixed-design ANOVA (

DIFFERENCES IN DYNAMIC STABILIZATION BETWEEN VOLLEYBALL AND RUGBY PLAYERS

The purpose of this study was to examine differences in the time to stabilization (TTS) between volleyball players (n=8) and rugby players (n=7). With no footwear, all participants performed 4 different hopping tasks (medial, lateral, and two forward hops) onto each foot. The AP and ML ground reaction force data were collected and used to compute the TTS for each condition. The TTS measures were averaged within the groups and compared by using eight independent-sample T-tests . Two out of eight conditions showed differences between the volleyball group and the rugby group. The rugby group stabilized more quickly on the R-foot 50% forward hop task (t(13)=3.722, ) and the volleyball group more quickly on the L-foot medial hop task (t(13)=-2.431, )

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