High and low-load resistance training produce similar effects on bone mineral density of middle-aged and older people: A systematic review with meta-analysis of randomized clinical trials.

Purpose: To compare the effects of high-load (≥ 70 of 1RM) and low-load (< 70 of 1RM) resistance training (RT) on femoral neck and lumbar spine bone mineral density (BMD) in middle-aged and older people.

Design: Systematic review with meta-analysis.

Data Source: English language searches of the electronic databases PubMed/Medline, Scopus and Web of Science.

Inclusion Criteria: (i) older or middle-aged (≥ 45 years old) participants of both sexes with or without comorbidities, (ii) studies that compared high-load (≥70% 1 RM) versus low-load (<70% 1RM) RT, (iii) studies that examined femoral neck or lumbar spine BMD.

Results: From 1052 studies found, six were included in qualitative and quantitative analysis. The meta-analysis revealed no difference between groups for femoral neck (weighted mean difference [MD] and 95% confidence interval (CI) = 0.00 g/cm [95% CI, -0.01 to 0.01]; P = 0.63) and lumbar spine (MD = 0.01 g/cm [95% CI, -0.00 to 0.02]; P = 0.12) BDM. There was a substantial heterogeneity for femoral neck (I = 47%; P = 0.07) and lumbar spine (I = 59%; P = 0.02). Subgroup analysis revealed a significant effect of high-load RT on femoral neck BMD when participants presented normal BMD values (MD = 0.01 g/cm [95% CI, -0.00 to 0.02]; P = 0.04) and on interventions lasting up to 6 months (MD = 0.01 g/cm [95% CI, -0.00 to 0.02]; P = 0.03).

Conclusion: Both high- and low-load RT have similar effects on femoral neck and lumbar spine BMD in aging people.