Why they did it?
There is strong evidence showing that regular physical activity and exercise participation is beneficial for a wide range of health-related outcomes. An intriguing aspect of exercise science is the fact that that every individual may adapt to an exercise stimulus differently. For example, after a standardised 12-week aerobic exercise training program, some may show a remarkable increase in cardiorespiratory fitness (aka responders), while in contrast, some may have no significant increase in fitness, or even a decrease! (aka non-responders). This responder vs non-responder phenomenon has led to some exercise scientists claiming that exercise programs should be individually tailored. At present much of the evidence around responder vs non-responder outcomes has been generated from studies using an aerobic exercise training stimulus on a single outcome (e.g. cardiorespiratory fitness). Little is known if this occurs during strength training participation across multiple outcomes. Therefore the aim of this study was to examine the individual responses to prolonged strength training among older adults.
How they did it?
In this experimental study, two groups of older adults aged 65+ years undertook either 12-weeks (n=110) or 24-weeks (85) supervised strength training. The link to the article describes the training program in detail. In brief, participants did strength training 3 sessions per week over the study duration (12-or-24 weeks). Exercises included leg press, leg extension, bench press, lat pull down and bicep curls. Assessments were taken pre-and-post intervention for lean body mass (assessed by Dual-energy X-ray absorptiometry [DXA]), leg strength (maximum leg press and leg extension) and physical function (chair-rise time).
What they found?
At the group level, for all outcomes, there were beneficial effects for lean body mass, muscle strength and physical function. Moreover, when compared to the 12-week group, the benefits were greater among the 24-week group. However, as expected, at the individual level, there was a wide range of differences across the outcomes measured. For example, some improved their muscle strength but did not improve their lean body mass. The key finding from the individual level analysis was that across all outcomes, there was a positive adaptive response on at least one training outcome apparent in every subject. In short, no one got worse, hence there were no absolute ‘non-responders’!
Ok, what does this mean to me?
Importantly, this study looked at multiple physiological markers related to strength training, and it was the first to show that all participants had a favourable response to at least one health-related outcome. From a scientific perspective, this highlights the need to look at many outcomes related to exercise training a not just depend on one or two. Also, this study showed that the longer the duration of the training the better the health outcomes. Fitness trainers should make clients aware that, even if they are not improving on some aspects of training (e.g. muscle strength), they may be getting other less obvious benefits (e.g. increasing muscle mass or physical function). Trainers should spread the word – ‘strength training for health, everyone’s a winner!’