Ageing effect on strength specific characteristics among generally active subjects

Abstract

Introduction: Strength level is a good predictor of health outcomes such as mortality or future disability. During an usual individual life span, strength and neuromuscular function are decreased, due to a reduction the muscle mass and the fiber type switch that manifests at the age of 50-60 years old. Physical activity can prevent, or at least reduce these changes. The fact that the physical activity level is also reduced by age, makes it difficult to distinguish between the effects of aging and those of a sedentary lifestyle. Therefore, this work attempts to study the differences in hand-grip strength, jump height and rate of force development as strength predictors, between physically active elderly and young adults. Material & Methods: 16 healthy and physically active adults formed 2 groups: experimental group (8 old adults, mean age 72.24 years old, SD 4.82) and control group (8 young adults, mean age 24.94 years old, SD 1.67). They all performed hand-grip strength, jump height and rate of force development tests. Statistical analysis were performed by using JASPS software. Results: Significant differences were found in hand-grip strength (t = 2.133, p = 0.07) and jump height (t = 9.949, p = 0.001), whereas no significant difference was obtained in rate of force development (t = -0.300, p = 0.773). Conclusions: There is a life-long reduction in whole body strength capabilities in active adults. Nevertheless, the importance of physical activity for keeping strength capabilities with increased age was evident. Furthermore, both hand-grip strength and jump height can be considered as reliable predictors of whole-body strength levels, whereas RFD should be taken with caution, due to its specifity.