Four weeks of high- versus low-load resistance training to failure on the rate of torque development, electromechanical delay, and contractile twitch properties.
The purpose of this study was to investigate the effects of 4-weeks of high- versus low-load resistance training to failure on rate of torque development (RTD), electromechanical delay (EMD), and contractile twitch characteristics. Fifteen men (mean±SD; age=21.7±2.4 yrs) were randomly assigned to either a high- (80% 1RM; n=7) or low-load (30% 1RM; n=8) training group and completed elbow flexion resistance training to failure 3 times per week for 4 weeks. The participants were tested at baseline, 2-, and 4-weeks of training. Peak RTD (pRTDV) and RTD at 0-30 (RTD30V), 0-50 (RTD50V), 0-100 (RTD100V), and 0-200 (RTD200V) ms, integrated EMG amplitude (iEMG) at 0-30, 0-50, and 0-100 ms, and EMD were quantified during maximal voluntary isometric muscle actions. Peak twitch torque, peak RTD, time to peak twitch, 1/2 relaxation time and the peak relaxation rate were quantified during evoked twitches. Four weeks of high-load, but not low-load resistance training, increased RTD200V. There were also increases in iEMG during the first 30 ms of muscle activation for the high- and low-load groups, which may have indirectly indicated increases in early phase motor unit recruitment and/or firing frequency. There were no significant training-induced adaptations in EMD or contractile twitch properties.
Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583.
N Dm
ND
Jenkins
T J
TJ
Housh
S L
SL
Buckner
H C
HC
Bergstrom
C M
CM
Smith
K C
KC
Cochrane
E C
EC
Hill
A A
AA
Miramonti
R J
RJ
Schmidt
G O
GO
Johnson
J T
JT
Cramer
D004551:Elbow Joint; D004576:Electromyography; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D055070:Resistance Training / Q000379:methods*; D019415:Torque; D055815:Young Adult