Early plateaus of power and torque gains during high- and low-speed resistance training of older women.

Periodization is the most effective approach to resistance training; however, optimal cycle lengths for older persons are not known. This study examined the durations of performance increments, plateaus, and decrements in women, ages 61-75 yr, over 9 wk of isokinetic training. After a 2-wk adaptation cycle, older women trained for either power (PWR; 4.73 rad/s; n = 9) or strength (STR; 1.05 rad/s; n = 8), 3 days/wk with a 1-day recovery between sessions. Repetitions were initially selected to equilibrate work volume between groups. Average power (AP), peak torque (PT), and total work (TW) curves were analyzed using forward and backward stepwise regression to ascertain inflections and plateaus. PWR training produced the highest AP, whereas STR produced the highest PT. TW was similar between groups. The AP curves of the PWR group initially showed a steep positive slope and then plateaued during week 3. The right leg plateau lasted throughout training, whereas the left leg showed another positive inflection during weeks 7 and 8. PWR group TW curves showed positive slopes throughout training. STR group PT curves for both legs showed initial positive slopes peaking between weeks 3 and 4 and declining thereafter. The TW curves for both legs showed slight negative slopes across the first 2 wk, steep positive slopes during weeks 3-6, and a final plateau. Because improvements plateau early during PWR and STR training, isokinetic training prescriptions for optimizing strength and power improvements in older persons should use cycles of 3-4 wk to maximize gains.

Differential increases in average isokinetic power by specific muscle groups of older women due to variations in training and testing.

BACKGROUND: As a person ages, leg speed and power decrease. These changes are associated with increased falls and reduced gait speed. It has been shown that upper leg training in younger persons results in increased strength and power at the specific speed at which resistance training is applied, although there are only limited data concerning speed-specific training effects on lower leg activity. However, because both upper and lower leg speed and power influence gait and balance, it is important to determine the training speeds that selectively improve these variables in older persons. METHODS: No studies have examined selective speed-specific changes in performance for the upper and lower leg muscles in older individuals. Therefore, we compared shifts in the power-velocity relationship after high-speed (HS) and low-speed (LS) isokinetic training of knee extensors (KE) and flexors (KF), dorsiflexors (DF), and plantar flexors (PF) in community-dwelling women (ages 61 to 75). Subjects were randomly assigned to a HS training, LS training, or control (C) group. Training occurred three times a week for 12 weeks. HS training occurred at 4.73 rad.s(-1) (knee) and 3.14 rad.s(-1) (ankle); LS training for both joint actions was at 1.05 rad.s(-1). RESULTS: HS training improved KE power at intermediate (3.14 rad.s(-1); p =.0007) and high (5.24 rad.s(-1); p =.0004) testing speeds. Neither the HS nor LS group showed any change in KF as a result of the training. Both LS and HS training improved DF power at all testing speeds; however, PF power improved only with LS training and only at 1.05 rad.s(-1) (p =.0132) and 3.14 rad.s(-1) (p =.0310). CONCLUSIONS: Our results suggest that, in older women, lower leg training should occur at lower training speeds than upper leg training. Additionally, attention to differential speed-specific training of knee and ankle actions could improve power production, mobility, balance, and other functional measures in older persons.