Resistance training and health in adults: an overview of systematic reviews
‘Overview of systematic reviews’… well we know it’s going to be a big one don’t we.
Aim; ‘determine the benefits and harms of resistance training (RT) on health outcomes in adults aged 18 years or older, compared with not participating in RT’
Criteria; Eleven systematic reviews were included, representing 364 primary studies and 382 627 unique participants
Conclusion; ‘RT was associated with a reduction in all-cause mortality and cardiovascular disease incidence, and an improvement in physical functioning. Effects on health-related quality of life or cognitive function were less certain. Adverse events were not consistently monitored or reported in RT studies, but serious adverse events were not common.
Systematic reviews for the remaining important health outcomes could not be identified. Overall, RT training improved health outcomes in adults and the benefits outweighed the harms.’
It won’t be surprising to many that much of what was included will not prove itself as novel information, and, depending on how one wishes to interpret the data, one may simply be led in to confirming one’s own biases, looking no further, delving no deeper and then moving on. However, my intrigue peaks at whether there was evidence that age, exposure dose, or type of RT influenced the effects on health outcomes. Is one able to draw any conclusions when the masses are condensed…? Or it simply that really there remains such a plethora of data that if left to their own devises one can condense it to mean whatever they want it to mean as the simple fact remains that something is better than nothing and as long as it is not taken in the extreme, (which in a systematic review is likely to be highlighted as an anomaly and thus discredited from the pool of subjects anyway) then RT will only serve to enhance one’s health across the board when compared to the sedentary slob… let’s consider the conjoining lifestyle factors that generically go alongside RT and the influence on comorbidities thus the likelihood of one popping their early clogs. Blunt but true.
Mortality;
Compared with no RT, performing RT was associated with 21% lower risk of all-cause mortality
RT was not associated with cancer mortality
The effects of more than 2 sessions of RT per week were not statistically significant
The meta-analysis showed that performing RT ≥2 times per week was not statistically significantly different from <2 times per week in terms of all-cause mortality
Physical Functioning
The effect of RT frequency on muscle strength comparing low to high showed no differences pre- vs. post-intervention in muscle strength gain. Note… volume was equated, ah that explains that then.
Did show a difference between upper and lower body; upper showing increased muscle gain from high frequency, whereas it failed to prove statistically significant for lower. Muscle fibre types and recoverability explain that one out.
Something to wake up for… ‘eccentric exercise (vs. concentric and isometric) and performing a prescribed number of repetitions (vs. performing repetitions to failure) resulted in greater muscle strength (maximal voluntary contraction) improvements’… but oh wait the lack of internal validity snuffs this study somewhat.
No differences in muscle strength (1RM) between fast versus slow-moderate speed in progressive RT
Circuit style RT 3x/wk led to greater muscle strength improvements. But hold up, again we’re comparing it to no RT at all. Sit your ass back down.
I should mention, if you choose to read the study, (which you probably won’t, hence my anecdote) that I do acknowledge, and as such have not intentionally been remis in my summation of many additional findings… I am aware that I have missed many a ‘finding’. My justification of this action being that should the study contain bias or have questionable internal validity then I didn’t include them here. Because this is my bias. Two can play at that game.
Health Related Quality of Life
‘We were unable to find a systematic review that met our inclusion criteria for the effect of RT on health-related quality of life’…Oh. Ergo, ‘Health-related quality of life was assessed using the physical function domains in the Short Form Health Survey 36-item or 12 item, and pain and vitality domains in the Short Form Health Survey 36-item’. In other words, if you can’t find the data you’re looking for using the methods and control measures you have proposed then just skew your methodology and parameters until you can wangle it to fit your promised manifesto… politicians and scientists a like I see. Either way, the manipulation was wasted as there was no statistically significant effect of RT on any of the health-related quality of life domains, nor any differences in pain or vitality scores when comparing high- versus low-intensity RT.
Adverse Effects
Of RT…? An inflated ego? Protein bloat? A grumpy girlfriend? That’s about it, surely?
Well my scepticism is seemingly correct albeit a little flippant. Once again, ‘unable to identify a systematic review that met the inclusion criteria and thus we selected a systematic review that had the highest percentage of primary studies that were eligible for the adverse event outcome’. Sigh.
The worst recorded was ‘falls’, (your own fault surely) muscle strain, bruising, or joint pain, (man up, execute the movement properly and check your ego).
CVD
In men; RT for >30 min had significantly reduced incident fatal coronary heart disease and nonfatal myocardial infarction by 23% compared with no RT.
Medium-term (7–23 weeks) and long-term (≥24 weeks) RT programs reduced systolic blood pressure, and diastolic blood pressure compared to no/habitual RT. Increasing only further in those >41yrs.
Frequency does seem to play more of a role on heart health as greater reductions in DBP relative to the control group were associated with performing RT at least 3 days per week versus less than 3 days per week.
Similar findings can be replicated to isometric contractions, hypertension and mean arterial pressure.
Cognitive Function
Moderate (55%–65% 1RM) and high (75%–85% 1RM) intensities of RT 3x/wk compared with a control group that performed the same exercises 1x/wk without overload showed improvement in cognitive function.
Other RCT reported no RT treatment effects for neurocognitive function when compared with no RT
Not to be missed; ‘identified no systematic reviews that met the inclusion criteria for the effect of RT on 6 important outcomes: incident type 2 diabetes mellitus, incident depression, brain health, incident cancer, fall-related injuries or falls, or bone health.’
Overall; the only thing we can be certain of is that it is good for you and reduces negative health complications for a number of confounding reasons and individual differences… the frequency, intensity or any specifics is yet to be established due to, yes you guessed it, a number of confounding reasons and individual differences.
https://cdnsciencepub.com/doi/full/10.1139/apnm-2020-0245#tab2
