Medicine and Health Sciences Commons^™

Enhanced Proprioceptive Acuity At The Knee In The Competitive Athlete, Carol Courtney, Rose Rine, Drew Jenk, P. Collier, Andrew Waters

Rose Marie Rine P.T., Ph.D.

STUDY DESIGN: Controlled laboratory study: cross-sectional.

OBJECTIVE: To determine if proprioception, measured by the threshold to detection of passive motion (TDPM), differed in individuals who regularly participate in moderate-intensity exercise for fitness as compared to individuals involved in high-intensity skilled exercise.

BACKGROUND: Previous research has been equivocal as to whether exercise training is associated with superior proprioceptive acuity, in particular, exercise that includes dynamic postural challenges such as cutting and pivoting.

METHODS: Two groups of 25 healthy individuals (18-32 years old) were recruited. One group consisted of individuals who performed moderate-activity level exercises for 5 to 10 hours per …

The Effect Of An 8-Week Bilateral Or Unilateral Lower Body Resistance Training Program On 20m Sprint Speed, Brendyn Appleby, Prue Cormie, Stuart Cormack, Robert Newton

Prue Cormie

A critical element of effective program design for athletic training is the mechanical specificity of the selected exercises. Traditionally, exercises such as weightlifting, deadlifts and squats are frequently used due to their ability to use substantial external resistance to develop strength, and their performance relationships to jumping and sprinting. However, jumping and sprinting are rarely performed bilaterally in the sporting arena and while unilateral exercises are deemed more sport specific, they have generally remained confined to rehabilitation programs.

Peak Force And Rate Of Force Development During Isometric And Dynamic Mid-Thigh Clean Pulls Performed At Various Intensities, Naoki Kawamori, Steven Rossi, Blake Justice, Erin Haff, Emido Pistilli, Harold O'Bryant, Michael Stone, Gregory Haff

Greg Haff

Eight male collegiate weightlifters (age: 21.2 +/- 0.9 years; height: 177.6 +/- 2.3 cm; and body mass: 85.1 +/- 3.3 kg) participated in this study to compare isometric to dynamic force-time dependent variables. Subjects performed the isometric and dynamic mid-thigh clean pulls at 30-120% of their one repetition maximum (1RM) power clean (118.4 +/- 5.5 kg) on a 61 X 121.9-cm AMTI forceplate. Variables such as peak force (PF) and peak rate of force development (PRFD) were calculated and were compared between isometric and dynamic conditions. The relationships between force-time dependent variables and vertical jump performances also were examined. The …

Maximum Strength And Strength Training - A Relationship To Endurance?, Michael Stone, William Sands, Kyle Pierce, Robert Newton, G Haff, Jon Carlock

Greg Haff

Endurance can be defined as the ability to maintain or to repeat a given force or power output. The sport performance-endurance relationship is a multi-factorial concept. However, evidence indicates that maximum strength is a major component. Conceptually, endurance is a continuum. The literature indicates that (a) maximum strength is moderately to strongly related to endurance capabilities and associated factors, a relationship that is likely stronger for high intensity exercise endurance (HIEE) activities than for low intensity exercise endurance (LIEE); (b) strength training can increase both HIEE and LIEE, the effect being greater for HIEE; (c) the volume of strength training …

Periodization Of Training, Guy Haff

Greg Haff

Not available

Use Of Stability Balls In Strength And Conditioning, L Landow, Guy Haff

Greg Haff

The use of stability ball training is controversial. Two authors below give opposing views as to the use of this training modality.

The Relationship Between Isometric Force-Time Curve Characteristics And Club Head Speed In Recreational Golfers, Brian K. Leary, Jason Statler, Brent Hopkins, Rachel Fitzwater, Tucker Kesling, Jacob Lyon, Brent Phillips, Randall Bryner, Prue Cormie, Guy Haff

Greg Haff

The relationship between isometric force-time curve characteristics and club head speed in recreational golfers. J Strength Cond Res 26(10): 2685-2697, 2012-The primary purpose of the present investigation was to examine the relationships between club head speed, isometric midthigh pull performance, and vertical jump performance in a cohort of recreational golfers. Twelve recreational golfers (age, 20.4 ± 1.0 years; weight, 77.0 ± 9.8 kg; height, 177.8 ± 6.3 cm; body fat, 17.1 ± 7.6%; handicap, 14.5 ± 7.3; experience, 8.9 ± 3.6 years) completed 3 testing sessions: (a) familiarization session and body composition measurements; (b) measurement of forcetime curves in the …

Resistance Training For Endurance Sports, Guy Haff, Stephanie Burgess

Greg Haff

Not available

Isometric Strength Of Powerlifters In Key Position Of The Conventional Deadlift, George Beckham, Hugh Lamont, Kimitake Sato, Michael Ramsey, Guy Haff, Michael Stone

Greg Haff

Objectives: To determine if force differences exist between isometric pulling positions corresponding to key positions of the deadlift. Design: Cross-sectional evaluation of isometric strength Methods: 14 powerlifters performed isometric pulls on a force plate at 3 key positions related to the deadlift (at the floor, just above the patella, and 5-6 cm short of lockout) and in the mid thigh pull position (MTP). A 1x4 repeated measures ANOVA was used to ascertain differences between the various pulling positions tested. Bonferroni-adjusted paired samples t-tests were used post-hoc. Results: Forces generated at each bar height were significantly different (F(3,39) = 51.058, p<0.05, η2=0.80). Paired samples t-tests showed significant differences between positions, revealing a trend of greater force generation at increasing heights for positions corresponding to the deadlift. Force generated in the mid thigh pull position was significantly higher than any other position. Conclusion: In positions corresponding to the deadlift, force generation increases at higher bar heights.

Training Integration And Periodization, Guy Haff, Erin Haff

Greg Haff

Not available

The Acute Effects Of Moderately Loaded Concentric-Only Quarter Squats On Vertical Jump Performance, Aaron Crum, Naoki Kawamori, Michael Stone, Guy Haff

Greg Haff

2012-Limited research exists examining the effect of moderately loaded conditioning activities that are employed as part of a strength-power potentiating complex (SPPC). Additionally, no studies to date have explored the effects of using a concentric-only quarter back squat protocol as part of an SPPC. Therefore, the purpose of this study was to examine the effects of a moderately loaded (50-65% of 1RM) concentric-only quarter back squat protocol on the occurrence of potentiation effects at various time points. Twenty men who could quarter back squat a minimum of 2.4 times their body mass (3.7 ±: 0.7 kg-per body mass) participated in …

Training Principles For Power, Guy Haff, Sophia Nimphius

Greg Haff

The ability to express high power outputs is considered to be one of the foundational characteristics underlying successful performance in a variety of sporting activities, including jumping, throwing, and changing direction. Numerous training interventions have been recommended to enhance the athlete's ability to express high power outputs and improve their overall sports performance capacity. This brief review examines the factors that underlie the expression of power and various methods that can be used to maximize power development.

Current Research: Training For Strength, Power, And Speed, Greg Haff

Greg Haff

summary: this research brief covers concurrent strength and endurance training in elite soccer players, the effect of hypertrophy training protocols with maximal loading on neural drive, the effect of cluster sets on power in jump squats, and the effect of age on repeated-sprint ability in youth soccer players

Neuromuscular And Endocrine Responses Of Elite Players During An Australian Rules Football Season, Stuart Cormack, Robert Newton, Michael Mcguigan, Prue Cormie

Prue Cormie

Purpose: To examine variations in neuromuscular and hormonal status and their relationship to performance throughout a season of elite Australian Rules Football (ARF). Methods: Fifteen elite ARF players performed a single jump (CMJ1) and 5 repeated countermovement jumps (CMJ5), and provided saliva samples for the analysis of cortisol (C) and testosterone (T) before the season commenced (Pre) and during the 22-match season. Magnitudes of effects were reported with the effect size (ES) statistic. Correlations were performed to analyze relationships between assessment variables and match time, training load, and performance. Results: CMJ1Flight time:Contraction time was substantially reduced on 60% of measurement …

The Relationship Between Isometric Force-Time Curve Characteristics And Club Head Speed In Recreational Golfers, Brian K. Leary, Jason Statler, Brent Hopkins, Rachel Fitzwater, Tucker Kesling, Jacob Lyon, Brent Phillips, Randall Bryner, Prue Cormie, Guy Haff

Prue Cormie

The relationship between isometric force-time curve characteristics and club head speed in recreational golfers. J Strength Cond Res 26(10): 2685-2697, 2012-The primary purpose of the present investigation was to examine the relationships between club head speed, isometric midthigh pull performance, and vertical jump performance in a cohort of recreational golfers. Twelve recreational golfers (age, 20.4 ± 1.0 years; weight, 77.0 ± 9.8 kg; height, 177.8 ± 6.3 cm; body fat, 17.1 ± 7.6%; handicap, 14.5 ± 7.3; experience, 8.9 ± 3.6 years) completed 3 testing sessions: (a) familiarization session and body composition measurements; (b) measurement of forcetime curves in the …

Knee Angle-Specific Emg Normalization: The Use Of Polynomial Based Emg-Angle Relationships., Jacob Earp, Robert Newton, Prue Cormie, Anthony Blazevich

Prue Cormie

The normalization of EMG signals to those recorded during a maximal voluntary contraction provides a valid construct for comparisons of relative muscle activity. However, the length dependence of muscle activation and purported, substantial, muscle translocation and changes in muscle architecture during dynamic movements presents a need for joint angle-dependent normalization processes. The purposes of the present study were to: (1) quantify variations in muscle activity across a large ROM, (2) determine the accuracy with which fitted EMG-joint angle curves accurately characterized these variations, and (3) compare peak (EMG-P) and average (EMG-A) EMG amplitudes obtained during a countermovement leg extension when …

Relationship Between Strength, Power And Sprint Performance In Professional Cricketers, Matt Inness, Prue Cormie, Robert Newton

Prue Cormie

No abstract available.

Factor Structure Of The Chinese Service Quality Assessment Scale, Siu-Yin Cheung, Eddie Lam, Jia-Wen Shao, Jennifer Mak

Jennifer Y Mak

The quality of service has been the major subject of interest for business and academia. The aims of this study were to investigate the service quality of fitness clubs in Hong Kong and Guangzhou and to examine the underlying factor structure of the Service Quality Assessment Scale (SQAS; Lam, Zhang, & Jensen, 2005) in the Chinese context.