Hirotsugu Yoshimura

What research says

For hypertrophy, several studies report little to no difference between free weights and machines. A systematic review and meta-analysis by Haugen et al. (2023; 13 studies, 1,016 participants) found no statistically significant difference in muscle growth (SMD -0.055, p=0.751) and no difference in jump performance. An 8-week RCT by Schwanbeck et al. (2020; n=46) likewise found equivalent increases in muscle thickness between the two. When effort and volume are matched, growth doesn't hinge on 'free weights vs machines.'

What research says

Body recomposition — losing fat while gaining muscle — is documented across multiple sources. A review by Barakat et al. (2020) concludes that recomposition can occur not only in beginners and those with obesity but also in trained individuals. The keys are progressive resistance training and a sound nutrition strategy with adequate protein — not necessarily a large weight gain. That said, this is a narrative review, and how much recomposition happens depends heavily on individual factors like training history and body-fat level.

What research says

There's almost no data directly measuring 'power leak' and showing a disadvantage. If anything, a small study by Sinclair et al. (2015) found squats were deeper with cushioned running shoes than barefoot, with greater knee flexion and rectus femoris activity — participants preferred barefoot, but no biomechanical basis for that preference was found. Conceptually, if you treat a soft, compressible surface as a 'mini unstable surface,' you might invoke Anderson & Behm (2004), who showed roughly a 60% drop in maximal force under unstable conditions. But that was a chest-press study, not direct evidence about shoes or squats.

What research says

For healthy knees, there's little basis for the idea that deep squats are harmful. A review by Hartmann et al. (2013) examining 164 studies reports that patellofemoral (kneecap) compressive stress actually peaks around 90 degrees, and that squatting deeper distributes load via a 'wrapping effect.' The concern that deep squats raise the risk of cartilage softening or osteoarthritis was deemed 'unfounded.' If anything, handling supramaximal loads in half or quarter squats may stress the knees and spine more over time. The premise, however, is a healthy knee and proper form.

What research says

When calorie intake is matched, fat loss is the same whether cardio is fasted or fed. In an RCT by Schoenfeld et al. (2014; 20 young women), four weeks of cardio three times a week under a hypocaloric diet produced no significant difference in body weight or fat loss between fasted and fed groups. This suggests fat loss is driven by total calorie balance, not workout timing.

What research says

The idea that transient post-exercise hormone spikes cause hypertrophy has been refuted by several studies. West et al. (2010) trained one arm of the same person under a 'low-hormone' condition and the other under a 'high-hormone' condition (with added leg work) for 15 weeks — with no difference in muscle growth or strength, even though hormones clearly rose on the high-hormone side. Morton et al. (2016; n=49) found post-exercise spikes in testosterone, GH, and IGF-1 did not correlate with gains in muscle size or strength. West & Phillips (2012; n=56) reported the same, with testosterone in particular showing no correlation.

What research says

Stretching alone hasn't been shown to prevent injury. A large meta-analysis by Lauersen et al. (2014; 25 RCTs, ~26,600 people) found a risk ratio of 0.963 for stretching — no significant protective effect. Strength training, by contrast, had a risk ratio of 0.315, substantially reducing injuries. In other words, current evidence says 'to prevent injury, build strength rather than stretch.'

What research says

There's no evidence that ab exercises alone reduce abdominal fat. In a 6-week RCT by Vispute et al. (2011; n=24), performing seven ab exercises five days a week under an isocaloric diet produced no significant change in body weight, body-fat percentage, waist circumference, or abdominal skinfold thickness. The only thing that improved was abdominal endurance (curl-up reps). Fat doesn't come off locally from targeted exercise.

What research says

A meta-analysis shows caffeine produces a small improvement in maximal strength and power. The effect is modest, but its direction is consistent.

What research says

The mechanism — transporting fatty acids into mitochondria — is well established. But a meta-analysis pooling over 1,000 people found weight loss that was statistically significant yet small in magnitude.

What research says

A meta-analysis of over 1,800 people found that gains in muscle and strength largely plateau around 1.6 g/kg/day of total protein. Beyond that, extra intake adds very little.

What research says

In an 8-week RCT of 42 resistance-trained men, blood zinc and magnesium rose, but there were no significant changes in testosterone or IGF-1, and no evidence that ZMA directly improved strength or muscle.

What research says

In people with normal kidney function, there's no solid evidence that high protein (up to ~2.2 g/kg/day) causes kidney damage; meta-analyses of trials show no harmful effect on glomerular filtration rate.