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.

Visceral Fat

Visceral fat is the fat around the abdominal organs. Because such fat is under the abdominal muscles, it cannot be detected by pinching the skin over the abdomen. In contrast, subcutaneous fat is located right under the skin and can be detected by a pinch and quantified by using a skinfold-caliper. Unfortunately, visceral fat is the most dangerous kind in that it produces hormones and inflammatory agents. Framingham heart study researchers reported that visceral rather than subcutaneous fat was associated with an indicator of cholesterol deposits in the aorta, the body's main artery.

Fortunately, exercise can have an impact on visceral fat. A study by Gary Hunter Ph.D., of the University of Alabama at Birmingham, showed that, among a group of women who lost an average of 24 lb by dieting, only those who stuck to an aerobic or strength-training exercise program of 40 minutes, twice a week, managed to keep off all of the visceral fat they lost. Those who did not exercise or who quit their exercise programs increased their visceral fat an average of 33% in the year following their weight loss.

Comparing weight training periodization programs

Weight training periodization has been widely recognized by strength and conditioning coaches to be a more effective means of increasing strength than staying with the same combination of repetitions and resistance over an extended period of time. Periodization basically involves making programmed changes from time to time in the number of repetitions performed in each exercise set, along with an increase in barbell weight as repetitions are decreased, and a decrease in barbell weight as repetitions are increased.

Periodization may be of the linear variety, by which the athlete makes progressive changes in the weight/rep combination during every training block of 1 or more weeks. For example the athlete may do 10 reps with a lighter weight for 2 weeks, then 8 reps with increased weight for 2 weeks, then 6 reps with more weight for 2 weeks, followed by 4 reps with even more weight for 2 weeks. A single repetition max lift may then be attempted before returning to the 10-rep scheme. This cycle may be repeated over an extended time period. The athlete generally gets stronger between cycles so that the weight at all repetitions is adjusted upwards, resulting in a continued increase in strength. Even more complex periodization models have been developed by strength coaches. For example, in daily undulating periodization, the athlete may change the repetition/weight scheme within a single week, with other changes occurring over more extended time periods.

A recent article in the Journal of Strength and Conditioning Research (Vol 23, no 9, pp 2437-2442, 2009) entitled, “Comparison between linear and daily undulating periodized resistance training to increase strength” by Prestes et al., compared these two regimens using 3 sets per exercise 4 times per week with 20 subjects in each training group. The linear program used 12, 10, 8, and 6 reps for a week each, repeating the entire cycle 3 times for a total of 12 weeks. The daily undulating program used 12 reps for half a week, 10 reps for the second half-week, 8 reps for the first half of the following week, and 6 reps for the second half-week. This pattern was repeated 6 times for a total of 12 weeks.

Although the results did not reach statistical significance because of individual differences in training response, the average increases in isometric strength (bench press, leg press, and arm curl) were considerably greater for the daily undulating periodization group than for the linear periodization group. This supports previous research showing the effectiveness of daily undulating periodization programs.

The Magic of Interval Training

The evidence continues to mount that interval training is very effective in a number of ways. For those not familiar with interval training, it involves short bouts of intense exercise (usually running, cycling or rowing) interspersed with longer periods of light exercise. An example involving running would be to warm up thoroughly first, then run a quarter-mile (~400m) at 85-90% of max speed, then walk or jog an eighth-mile (~200 m), repeating the run/walk cycle for 8-10 repetitions followed by a warm-down. There are many variations of interval training, and some involve even shorter bursts of intense exercise (e.g. 200m runs).

A recent article in the Journal of Strength and Conditioning Research (Tanisho and Hirakawa, vol 23, no. 8, 2009, pages 2405-2410) reinforces the efficacy of interval training. The subjects were 18 Japanese male lacrosse players who trained 3 days/wk for 15 weeks on an exercise cycle. The continuous-training (CT) group pedaled continuously for 20-25 minutes, while the intermittent-training group (IT) alternated 10-second max-speed pedaling with 20-second easy pedaling, for a total of 10 intervals (total time = 5 minutes). There was also a control group that did no training. Interestingly, the IT group improved almost as much (10%) in the maximal oxygen uptake test (gold standard of aerobic fitness) as the CT group (12%). However, only the IT group improved in maximal power output. The IT group was also the only one to improve in fatigability, measured as the ability to maintain cycling power output over 10 intervals of 10-second max-speed pedaling interspersed with 40-second recovery periods.

One would have to conclude that the interval training produced amazing results. The 5-minute interval training sessions produced almost as much increase in aerobic capability as 20-25 minutes of endurance training. Yet the interval training also produced significant gains in maximum power and in resistance to fatigue from repeated intense exertions bouts. IT was a truly remarkable and time-efficient form of training.

This type of training is clearly advantageous for most team sports, which generally involve short bursts of intense activity interspersed with mild-to-moderate activity. The effectiveness of the interval training supports the concept of Specificity of Training, by which training is most effective when it reflects important aspects of the sport in which improvement is sought. Distance running is not effective for most team-sport athletes because it has been shown to actually reduce max power output, needed for jumping and sprinting. Thus long runs are only recommended for athletes in endurance sports.

A word of caution is in order. No-one should engage in an exercise program without first determining whether a doctor's clearance is needed first. See our Exercise Risk Questionnaire. Even if you are cleared for general exercise, you may not be ready yet for interval training, which should only be undertaken by people who are already well-conditioned. It is an intense form of exercise that puts considerable strain on the heart, lungs, muscles, and bones. Running intervals can easily cause muscle pulls or other musculoskeletal injuries, so very thorough pre-interval warmups are necessary. Cycling and rowing intervals involve less impact and peak force on the musculoskeletal system than running and are thus less likely to produce injury. However, any interval training must be approached with caution. The key points are to start with a well-conditioned individual, warm up very thoroughly, and start at a moderate level of difficulty, increasing the intensity of intervals over a period of several weeks.