Multiple-joint velocity-spectrum strength/power development consequent to repetition manipulation

Various repetition strategies are employed in typical weight-training programs. Strength is purportedly best developed using relatively few repetitions against great resistance. Strength in this context has typically been measured isotonically (dynamic constant external resistance or DCER) by performing a one-repetition maximum (1 RM). Multiple-joint isokinetic (velocity controlled) strength assessments are now available which may enable us to emulate movement patterns and velocities with those occurring in everyday activities while providing us with force and power information that heretofore has been difficult to obtain. Therefore, we assessed the effects of various repetition schemes during heavy-resistance training on multiple-joint isokinetic performance. METHODS.

Volunteers participated in 12 weeks (36 sessions) of variable-resistance weight training (8 different exercises) in one of the following programs: I-3 sets x 3-4 RM; II-3 x 9-10 RM; III-3 x 15-16 RM; IV, control.

48 apparently-healthy young men (18 to 34 years of age, X = 23.2) who had not participated in systematic heavy-resistance training during the previous year.

Pre and post velocity-spectrum tests were conducted for both the squat (0.41, 0.65, 0.90, 1.14, and 1.39 m x s(-1) and bench press (0.50, 0.79, 1.09, 1.39 and 1.69 m x s-1) at which time peak force and peak power were measured. Force and power measurements were adjusted to control for body weight (N/kg and W/kg, respectively). Change (delta) scores were used for comparisons.

One-way ANOVA s indicated that when compared to controls, improvements in force were significantly (p < 0.05) greater only at the slowest velocity (squats: Group II > Control; bench presses: Groups I, II, III > Control). However, changes in power were significantly (p < 0.05) greater than for controls at all 5 velocities tested (squats: Groups I, II > Control; bench presses: Groups I, II > Control except at 1.69 m x sec-1) where only Group I > Control).

Due to the mixed findings for force improvements consequent to the various repetition schemes, conclusions are somewhat tentative. It appears, however, that strength increases only for slow velocities in young, previously untrained men consequent to 3 months of a relatively wide range of RM schemes using variable-resistance equipment. Power, on the other hand, appears to increase in the same subjects across a velocity spectrum for both squats and bench presses when no more than 10 RM are performed per set.