Weight-Training with Slow vs. Normal-Speed Repetitions

Weight-training with slow and super-slow repetitions has been promoted in some quarters as superior to normal-speed weight training. An article by Tanimoto et al. in the Journal of Strength and Conditioning Research (vol. 23, no. 8, 2009) tested this hypothesis.

Experimental Method:
Twenty-four young men performed 3 sets of barbell squat exercise,  twice a week for 13 weeks, and were equally distributed among the following 3 groups:

     - Control Group: no organized exercise
     - Slow-Repetition Group: 3 sec descending, 3 sec ascending, no rest between reps
     - Normal-Speed-Repetitions: 1 sec descending, 1 sec ascending, 1 sec between reps

The two lifting groups each did 8 reps with the most weight they could handle for that number of reps and the assigned speed (metronome-timed). Because slow reps are more difficult, the weight used was about 60% of max for the slow group and about 85% of max for the fast group.

Results:
Both training groups significantly improved both their max squatting strength (Slow: 34%, Fast: 28%) and their lean thigh muscle volume (Slow: 2.5%, Fast 3.6%). However the groups did not differ significantly in their percent gains in these two parameters. The authors concluded that slow resistance-training is just as effective as normal-speed training for improving muscle strength and size, and has the additional advantage of being safer because of lower musculoskeletal forces and less elevation of blood pressure.

One area in which the groups differed was in their muscle electrical activity while riding a bicycle at a typical speed and resistance. The slow-trained group developed a more unusual pattern of muscle activation and force application. The authors felt this indicated that slow-speed strength-training may have some unfavorable effects on dynamic physical activities, like those typical of sports. However, they felt that, because of the safety advantages of slow-speed weight-training, the method can be combined for sport training with some fast and exposive lifts (e.g. cleans), “cheating technique”, and plyometrics (e.g. jumping).

Strength Training Helps Seniors in Daily Living Activities

A study by Hanson et al., published in the Journal of Strength and Conditioning Research (vol 23, no 9, 2009) tested the effectiveness of strength training in improving the ability of elderly people to perform activities of daily living. 35 men and 65 women, all initially sedentary, were trained 3 times per week for 22 weeks on Keiser pneumatically-resisted machines. The first 10 weeks involved only knee extension training, but the routine for the final 12 weeks included knee-extension, chest press, seated row, seated leg curl, abdominal crunch, and alternating leg press. The subjects improved significantly in knee-extension strength and power, leg-press strength, and fat free mass. They also became significantly faster in functional activity tests such as a 20-foot walk, repetitive (5x) standing up from and sitting down on a chair, and getting up from a chair and walking 16 feet. Improvements in strength, power, and fat-free mass correlated positively with improvement in the functional activities. This study shows that resistance training can improve strength and power at any age and such changes lead to improvement in performance of daily life activities.