Effects of low load versus high load to failure resistance training on strength and executive function in older adults

Abstract

Muscular strength training is recommended to older adults to maintain mobility and quality of life by preventing sarcopenia. Research in younger individuals indicates that resistance training performed to failure can stimulate similar muscle growth across a wide range of loads (Schoenfeld et al., 2017). For older adults, low load resistance training may offer a joint-friendly alternative while still promoting muscle hypertrophy. Moreover, resistance training is associated with maintained cognitive function (Herold et al., 2019).

The aim of this study was to compare the effects of eight weeks of low load resistance training to failure compared to high loads on muscle strength and executive function in older adults.

In this randomized controlled trial 16 (6 men, 10 women, 64.7 ± 4.2 years, 24.0 ± 3.3 kg/m²) older adults performed resistance training at 40% or 60% 1-repetition maximum (RM) to failure, two times per week for 8 weeks. Leg extension and curl with two legs were performed, and leg press with each leg separately. 1-RM was estimated by a 5-RM test. Executive function was assessed by computerized Eriksen-flanker (EF) and Go/No-Go tests (GNG). Mixed effects models were used accounting for differences in sex, age and BMI. Percentage effect sizes and 95% confidence intervals are reported.

Leg curl and extension strength increased on average by 9.4% (-11.7; +30.6) and 10.0% (-7.1; +27.2 more in the low load group. Leg press performance was increased more in the high load group. The left side improved by +16.9% (-0.3; 33.5) and the right side by 6.9% (-0.8; +14.7). For executive function, processing speed in low demand tasks increased by 13.4% (-0.4; +26.4) in the EF test and 6.7% (-12.7; +26.1) in the GNG test in favor of the low load group while in high demand tasks it increased by 18.4% (-3.7; +40.6) in the EF test in favor of the low load group but was decreased in the GNG test by 16.4% (- 9.7; +42.6). Interference costs in the EF test were increased by 181% (-4.4, +368) in the high load group.

Both groups improved their strength with slight advantages to low or high load training depending on selected exercise. To the authors’ surprise, cognitive function seemed to be negatively affected by high load training to failure with declines in processing speed in both cognitive tests. Cognitive inhibition parameters showed diverging results. The potential of a positive effects of lower loads on cognitive performance in the presence of similar improvements in strength should be investigated further and should be considered for older adults, a population highly interested in maintaining cognitive health.

References

Schoenfeld, B. J., Grgic, J., Ogborn, D., & Krieger, J. W. (2017). Strength and Hypertrophy Adaptations Between Low- vs. High-Load Resistance Training: A Systematic Review and Meta-analysis. Journal of Strength and Conditioning Research, 31(12), 3508–3523. https://doi.org/10.1519/jsc.0000000000002200

Herold, F., Törpel, A., Schega, L., & Müller, N. G. (2019). Functional and/or structural brain changes in response to resistance exercises and resistance training lead to cognitive improvements—A systematic review. European Review of Aging and Physical Activity, 16, 10. https://doi.org/10.1186/s11556-019-0217-2