Resistance training with moderate loads in the 8 to 12 repetition range provides greater bone mineral density benefits than performing high repetitions with light weights.
"also at the 8 to 12, you get the added benefit of loading the skeleton. So, you get the bone mineral density benefits that you don't get as much if you're doing a light weight and doing 30 reps." (said at 0:50:50)
The speaker claims that resistance training in the 8 to 12 repetition range provides bone mineral density (BMD) benefits that are not achieved as much with light weights at 30 repetitions. While high-intensity, heavy-load resistance training (e.g., >80–85% 1RM, typically 5–12 reps) is well documented to elicit clinically meaningful bone density improvements compared to low-load home control programs (e.g., LIFTMOR trial), systematic meta-analyses directly comparing high-load to low-load resistance training show overall similar effects on lumbar spine and femoral neck BMD in middle-aged and older adults. Furthermore, low-load, high-repetition programs (e.g., BodyPump or high-rep weight training) have also been shown to significantly increase or preserve BMD compared to non-lifting controls. Thus, asserting that high-repetition light-weight training does not provide comparable bone mineral density benefits overstates the distinction between load ranges.
- contradicts: Low load, high repetition resistance training program increases bone mineral density in un… (The Journal of sports medicine and physical fitness 2017)
"Compared to baseline, BMD significantly increased for S-WEIGHT in the arms (+4%, P<0.001), legs (+8%, P<0.01), pelvis (+6%, P<0.01) and lumbar spine (+4%, P<0.05)... These results suggest that a low load, high repetition resistance training program may be an effective method to improve bone mass in adults." (abstract, results and conclusions)
pubmedfull study (doi) - supports: High-Intensity Resistance and Impact Training Improves Bone Mineral Density and Physical F… (Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research 2018)
"HiRIT (n = 49) effects were superior to CON (n = 52) for lumbar spine (LS) BMD (2.9 ± 2.8% versus -1.2 ± 2.8%, p < 0.001), femoral neck (FN) BMD (0.3 ± 2.6% versus -1.9 ± 2.6%, p = 0.004)" (abstract, results, passage verified)
pubmedfull study (doi) - contradicts: High and low-load resistance training produce similar effects on bone mineral density of m… (Experimental gerontology 2020)
"The meta-analysis revealed no difference between groups for femoral neck (weighted mean difference [MD] and 95% confidence interval (CI) = 0.00 g/cm 2 [95% CI, -0.01 to 0.01]; P = 0.63) and lumbar spine (MD = 0.01 g/cm 2 [95% CI, -0.00 to 0.02]; P = 0.12) BDM... Both high- and low-load RT have similar effects on femoral neck and lumbar spine BMD in aging people." (abstract, results and conclusions, passage verified)
pubmedfull study (doi)