In one study, participants performed a 3-second eccentric biceps contraction with maximum effort. This is the same as slowly lowering a dumbbell from a bent arm to a straight arm position. The emphasis is on the slowing down phase rather than the lifting phase.
Research has shown that this type of exercise, when performed for 3 seconds while lowering weight, can significantly improve muscle strength when done 5 days per week, every day for 4 weeks. The duration of the study was 4 weeks and participants exercised 5 out of 7 days per week.
The participants in this particular study were divided into two groups in order to compare different frequencies of exercise. One group performed the 3-second eccentric contraction twice per week and the second group did the same identical exercise three times per week. After the completion of the 4 week study period, the biceps muscles of all participants were measured and compared.
Twice Per Week
The group that only exercised twice per week completed all the required repetitions over the 4 weeks. However, when their biceps were measured there were no significant changes in muscle size or strength detected. However, the group that exercised 3 days per week saw a small but statistically significant increase in concentric muscle strength of 2.5%. Concentric strength refers to the muscle’s ability to contract and produce force while shortening in length.
According to other similar studies, shorter eccentric workout sessions performed more frequently such as 5 days per week are more effective at stimulating muscle growth than only completing 2 or 3 longer sessions over the course of a week. Consistency seems to play an important role.
Three Times Per Week
The results of this current study suggest that at least three training sessions per week, ideally spaced out, are required to reap noticeable benefits of from simple bodyweight exercises, such as a single 3-second eccentric biceps contraction. The gains might be small as observed in this study, but they are still statistically significant.
Three training sessions per week is adequate to see some improvements, but five sessions per week is likely better for optimal results. Even though the group that trained 3 days per week saw positive results, adding a few extra days of the same exercise per week will likely have an even greater cumulative impact over time. The more frequent training provides more frequent stimulation to the muscles.
In fact, participants in an earlier similar study who performed the single 3-second eccentric exercise five days a week saw over 10% gains in concentric strength, which was far greater than the 3 day per week group in this current study. This demonstrates the potential benefits of increased weekly training frequency when possible.
However, the researchers also stressed that daily training for 7 days per week is not necessary to achieve substantial additional benefits for this type of simple exercise. Muscles still need adequate rest between workouts to recover, rebuild and grow stronger.
It is during rest periods between workouts that muscles actually adapt to the stimulation and develop increased mass and strength to be better prepared for future challenges. So while frequent stimulation helps drive adaptations, rest is also critically important.
In this particular study, the exercise sessions were very brief at only 3 seconds while the rest periods between sessions were approximately 28,800 times longer. This demonstrates that muscles will positively respond to small amounts of stimulus even when it is vastly outweighed by non-training time.
More research is still necessary though to determine if these observed results can be reasonably extrapolated to other types of exercises as well as higher volumes and intensities of training. Not all exercise prescriptions will necessarily follow similar patterns.
It is also not always ideal or advisable to simply increase the amount of time spent exercising, whether that involves strength training, aerobic exercise, flexibility training etc. There appears to be a point of diminishing returns and also an increased risk of injury, fatigue and overtraining.
Some research suggests that shorter daily exercise sessions such as 20 minutes per day can be more manageable and sustainable than longer 2-hour workout sessions performed only 2-3 days per week when it comes to improving general health and fitness. Even shorter daily workouts of around 5 minutes might still produce meaningful benefits over time. More studies are still needed to continue investigating these questions around frequency, duration and type of exercise at various levels. However, the current research certainly seems to emphasize the importance of regular exercise, even if fairly short in length, rather than sporadic longer sessions.
In summary, these research findings demonstrate that the human body can respond positively to exercise stimulus that is performed regularly. Even small amounts of daily training, when repeated consistently over time, can trigger substantial cumulative fitness and health gains. But recovery time is also essential to allow the exercise adaptations to fully develop. Overall it highlights the importance of regular exercise participation as a lifestyle habit rather than viewing exercise as isolated events done occasionally.