Study archive · page 36

Flywheel resistance training improved change of direction performance more than traditional resistance training in male athletes, in a meta-analysis of seven studies. Two or fewer sessions a week, and 12 or fewer sessions in total, produced the largest effects.

⚠What it shows: Promising but thin: pooled results from just seven studies, all in male athletes, so nobody knows yet whether it holds for women or everyday gym-goers. The studies also varied in sports and programmes, which makes the exact size of the flywheel advantage uncertain.Meta-analysis · Int J Environ Res Public Health

A meta-analysis of 13 randomised trials found that adding neuromuscular electrical stimulation to resistance training produced modestly greater gains in strength and muscle mass than lifting alone.

⚠What it shows: Worth taking seriously, though the edge is small: results pooled from 13 trials where people were assigned at random favoured the combination for both strength and size. The strength studies disagreed with each other quite a bit, so the true size of that benefit is uncertain.Meta-analysis · Eur J Appl Physiol

Pooling 162 randomised trials with 10,475 adults aged 18 to 81.6 years, exercise produced small to moderate improvements in bone mineral density at five of six skeletal sites, including the femoral neck (g 0.28) and lumbar spine (g 0.22). The authors stress that rankings of which exercise type wins, and the suggested dose peak near 1100 MET-min/week for lumbar spine, are exploratory rather than prescriptions.

⚠What it shows: The headline effect is solid, the fine detail is not: results pooled from 162 randomised trials in 10,475 adults, with confidence ranging from high at the femoral neck down to very low at the total hip. The comparisons between exercise types were imprecise, the studies disagreed with each other, and the dose figures shifted depending on where the model's edges were drawn.Review · Bone

Elastic band training improved muscle strength and functional performance compared with no exercise in healthy adults, according to a review pooling five trials. Against other resistance training methods, bands produced similar strength gains but were inferior for functional performance.

⚠What it shows: Useful but thin: only five trials of healthy adults made the cut in this sweep of the evidence, three of them high quality. Bands matched other resistance methods for strength but came out behind them on functional performance, so this is a green light for strength specifically.Meta-analysis · J Phys Act Health

In adults aged 60 or older, resistance exercise significantly improved muscle-specific strength, the force produced per unit of muscle mass, while nutritional supplements, aerobic exercise and combined approaches showed no significant benefit across 41 pooled trials with 3,141 participants.

⚠What it shows: Strong for lifting, open for everything else: results pooled from 41 trials covering 3,141 adults aged 60 and over, though the trials trained and tested people in very different ways. The null results for supplements and aerobic work mean unproven rather than disproven.Review · Ageing Res Rev

Pooled results from 19 randomised trials in 768 healthy adults found that taking collagen peptides daily alongside several weeks of training produced small but significant gains in fat-free mass (SMD 0.48), tendon morphology (SMD 0.67), muscle architecture (SMD 0.39) and recovery of reactive strength 48 hours after muscle-damaging exercise (SMD 0.43). Maximal strength shifted least of all, at SMD 0.19.

⚠What it shows: Decent evidence for a supplement, with sensible limits: results pooled from 19 randomised trials in 768 healthy adults who supplemented for at least eight weeks while training. The authors rated their own confidence as moderate for body composition, low for most outcomes and very low for the tendon measurements, so the size of these effects could still move.Meta-analysis · Sports Med

Pooled results from 59 randomised trials with 3802 participants found green tea extract produced significant reductions in body mass, BMI and body fat percentage, alongside lower malondialdehyde and higher adiponectin and total antioxidant capacity. Fat mass, leptin and ghrelin did not change, and certainty across outcomes ranged from low to high.

⚠What it shows: Broad but uneven: results pooled from 59 randomised trials in 3802 participants, with the authors' confidence ranging from low all the way to high depending on the outcome. The reductions were statistically significant rather than large, and fat mass itself did not move.Meta-analysis · Br J Nutr

Pooled results from six randomised trials in 476 adults found gum arabic supplementation modestly reduced weight and BMI (an average BMI drop of 0.38) and lowered fasting blood glucose, though the glucose results varied widely between studies.

⚠What it shows: Early and shaky: just six trials with 476 adults in total, follow-up periods were short, and the blood sugar results disagreed sharply between studies. The weight and BMI changes were consistent across trials but small.Review · J Diabetes Metab Disord

Adults with long COVID symptoms had a peak oxygen uptake 4.9 mL/kg/min lower than recovered peers when tested more than 3 months after infection, in a meta-analysis of 9 studies. Deconditioning was common but not the whole story: abnormal oxygen extraction by the muscles, dysfunctional breathing and blunted heart-rate responses were also described.

⚠What it shows: Treat this as a credible signal rather than a settled number: results pooled from 9 studies covering 464 people with symptoms and 359 without, and the certainty was rated low. The underlying studies were small, prone to bias and defined long COVID differently from one another.Meta-analysis · JAMA Netw Open

Pooled results from 10 randomised trials covering 400 adults with overweight or obesity found exercise training improved flow-mediated dilation, a marker of blood vessel function; the benefit was clear for aerobic training while resistance training fell just short of statistical significance.

⚠What it shows: Encouraging but thin: results pooled from 10 trials covering just 400 adults, and the quality checks raised some concerns, so the authors themselves urge caution. Lifting fell just short of a clear effect, which leaves its role unresolved rather than disproven.Meta-analysis · Sci Rep

Pooling 17 trials in 576 healthy women, exercise produced modest improvements in blood lipids: total cholesterol fell by 5.77 mg/dL, triglycerides by 5.60 mg/dL, and HDL cholesterol rose by 4.49 mg/dL. Combined training was most effective for triglycerides and total cholesterol, while aerobic exercise significantly raised HDL.

⚠What it shows: A real but small effect: results pooled from 10 articles covering 17 trials with 576 healthy women in total. The trials tested different types and intensities of exercise, so this cannot tell you how much or how hard to train to get the same shift.Meta-analysis · J Physiol Biochem

Across three pooled analyses spanning 15 years of research, exercise was associated with reduced anxiety, but only aerobic forms showed the effect. Sessions of at least 21 minutes appeared necessary, and programmes needed to exceed 10 weeks to shift a person's underlying anxious disposition.

⚠What it shows: Robust in direction, fuzzy on dose: three sets of results pooled from 15 years of research agree that exercise lowers anxiety, but only the aerobic kind, and it worked no better than relaxation techniques. The true minimum session length is still unclear because other factors muddied that finding.Meta-analysis · Sports Med

Physical exercise had a positive and significant effect on anxiety in older adults in a meta-analysis of 17 studies published between 2005 and 2021, with consistent results across two different ways of pooling the data.

⚠What it shows: Encouraging, but the field is thin: results pooled from 17 studies of older people showed a clear drop in anxiety scores, yet the authors themselves call for higher quality research before the size of the benefit can be trusted.Meta-analysis · Comput Math Methods Med

Across six large national cohorts in Europe, North America, Asia and Africa covering 89,056 middle-aged and older adults, declines in cognitive function were consistently associated with worsening depression scores, with an overall effect of -0.094.

⚠What it shows: A strikingly consistent pattern, but researchers followed people rather than testing anything on them, so it cannot say whether fading cognition worsens mood or the reverse. The link held across 89,056 adults on four continents and across age, sex, drinking habits and marital status.Meta-analysis · J Affect Disord

Across nine pooled trials in 627 people, heat therapy reduced short-term pain and improved grip strength in hand osteoarthritis. Combined approaches such as paraffin and mud treatments outperformed heated gloves alone.

⚠What it shows: Solid for the short term: results pooled from nine trials in 627 people back the pain relief and grip gains, but the trials delivered heat in different ways and only tracked people briefly. Nobody knows yet whether the benefit lasts.Meta-analysis · J Rehabil Med

Exercise significantly increased bone mineral density at the lumbar spine and femoral neck in older adults, in a meta-analysis of 19 randomised trials with 1577 participants. Programmes combining impact activity with resistance training loading, and odd-impact protocols, were the effective types; low-impact and resistance-only exercise showed no significant change.

⚠What it shows: Strong by exercise-science standards: 19 trials with 1577 older adults, moderate to high quality, and no sign that negative results were left unpublished. The bone gains were small and results for some exercise types disagreed with each other, so the ideal programme is not yet settled.Meta-analysis · Age (Dordr)

Exercise brings small but significant reductions in pain and disability for people with chronic low back pain, and of the eight programme and trial features examined, only dosage, the total amount of exercise delivered, was linked to how well it worked.

⚠What it shows: Solid footing: this pooled the randomised trials of exercise for chronic low back pain and the benefit, though small, held up. It compared whole studies rather than individual patients, so it cannot say which kind of person benefits most, and the search only ran to 2008.Meta-analysis · Phys Ther

Greater exposure to ultra-processed food was associated with higher risks across 32 health outcomes in an umbrella review of meta-analyses covering nearly ten million people. Evidence was rated convincing for cardiovascular disease related deaths (risk ratio 1.50, a 50% higher risk), type 2 diabetes, anxiety and common mental disorders.

⚠What it shows: As strong as diet-tracking evidence gets without a trial: findings pooled from dozens of studies following nearly ten million people, so the pattern is unlikely to be a fluke. It still cannot prove the food caused the harm, and most of the underlying evidence was rated low or very low quality.Systematic review · BMJ

Diets rich in beta-glucans, the fibre found in oats and barley, lowered systolic blood pressure by 2.9 mmHg and diastolic by 1.5 mmHg for a median 4 g increase, in pooled trials of healthy adults; higher fibre intake overall produced no significant reduction.

⚠What it shows: Solid for the oats finding: results pooled from trials of healthy adults, 18 studies in the final numbers, all lasting at least six weeks. Fibre overall showed no clear effect on blood pressure, so the case here is for beta-glucan sources specifically, not fibre in general.Meta-analysis · J Hypertens

Meditation-based programmes lasting 4 to 12 weeks improved self-reported sleep quality in adults aged 55 and over with mild cognitive impairment, with a moderate to large pooled effect, and were also linked to less anxiety, stress and depression.

⚠What it shows: Promising but not settled: results pooled from seven small studies in 434 older adults, some without random assignment, and the studies disagreed with each other on how big the benefit is. Sleep was mostly self-reported rather than measured objectively.Review · Geriatr Nurs

Pooled results from 10 randomised trials in 2134 adults with insomnia or poor sleep found cannabinoids reduced insomnia severity and improved sleep quality scores, increased total sleep time by 33.99 min, lifted sleep efficiency by 4.31% and modestly cut time to fall asleep by 12.0 min. Side effects, mostly mild dizziness and dry mouth, were roughly four times more frequent than with comparators, with no serious harms recorded.

⚠What it shows: Encouraging but not the last word: results pooled from 10 randomised trials in 2134 adults, comparing cannabinoids against placebo or melatonin. The trials were mostly short, so the right dose and whether the benefit lasts are both unresolved, and mild dizziness and dry mouth were clearly more common.Review · Sleep Med

Strength training on its own reduced total cholesterol, triglycerides, LDL cholesterol and C-reactive protein in adults, while raising HDL cholesterol and adiponectin, in a meta-analysis of trials comparing lifting with no exercise.

⚠What it shows: Solid pooled evidence: results pooled from many adult trials comparing lifting alone with a group that did not train, and all six blood markers moved the right way. The shifts were small to moderate, and the search only runs to May 2017, so newer trials are missing.Meta-analysis · J Phys Act Health

Vigorous aerobic exercise and HIIT ranked most likely to be the best interventions for reducing visceral fat in a pooled comparison of 84 randomised trials covering 4836 adults with overweight or obesity. Resistance training ranked least effective and did not reduce visceral fat in women or in people with body fat of 40% or more.

⚠What it shows: About as broad as exercise evidence gets: 84 trials and 4836 adults with overweight or obesity, pooled and ranked against each other. The rankings reflect the probability of being best rather than certainty, and why lifting failed to shift visceral fat in women needs more study.Meta-analysis · Obes Rev

Interactive digital tools for self-managing low back pain have a weak evidence base: across 6 completed randomised trials with 2,706 adults, only one showed a benefit over control, though none showed harm.

⚠What it shows: Take the app-store hype down a notch: a sweep of all the studies up to March 2016 found just six completed trials with 2,706 people, and only one favoured the digital tool. Participants were mostly white, well educated and middle aged, so nobody knows whether these tools help anyone else.Meta-analysis · J Med Internet Res