Effect of training and exercise cessation on functional capacity and strength in older adults

Résumé

Objectives: This PhD Thesis aimed i) to determine whether the benefits of long and short training programs on functional capacity persist after short and long inactivity periods in institutionalized older adults with sarcopenia and ii) to analyze the repeatability and sensitivity of the field-based isometric knee extension (IKE) test in older adults living in nursing homes, as well as its relationship with functional capacity and body composition. Method: Article 1 - Twenty-four institutionalized older adults (87.1 ± 7.1 years, 58.3% women) diagnosed with sarcopenia were allocated into 2 groups: the Long Training-Short Detraining (LT-SD) group completed 24 weeks of supervised Vivifrail training followed by 6 weeks of detraining; the Short Training-Long Detraining (ST-LD) group completed 4 weeks of training and 14 weeks of detraining. Changes in functional capacity (Short Physical Performance Battery [SPPB] and Time Up and Go [TUG]) and handgrip strength were evaluated at baseline and after training and detraining periods. Article 2 - Thirteen institutionalized older adults (87.1 ± 10.9 years, 46% women) were recruited from a nursing home. The variability of maximal isometric force registered in IKE trials performed on the same day was used to examine intra-session repeatability, whereas inter-session repeatability was analyzed by comparing maximal isometric force from two different days. Standard error of measurement (SEM) was reported in both absolute (N·kg-1) and relative terms (coefficient of variation, CV). Furthermore, evaluations of functional capacity (Handgrip, Gait Speed, TUG, and Sit-to-stand tests) and body composition (appendicular lean mass adjusted by BMI, ALM/BMI) were conducted. Article 3 - Thirty-four institutionalized older adults (84,4 ± 9,7 years, 44% women) completed a 4-week Vivifrail training. Moreover, a subsample of 15 participants (86,0 ± 7,6 years, 40% women) was re-evaluated after a 14-week inactivity period. Changes in functional capacity, handgrip strength, and IKE test were analyzed. The sensitivity of the IKE test was examined by comparing the changes generated in this test against the repeatability of the protocol. Results: Article 1 – The Vivifrail training was highly effective in the short term in increasing functional and strength performance (effect size, ES= 0.32-1.44; p< 0.044), except for handgrip strength in the LT-SD group ( ES= 0.48; p= 0.48). Continued training for 24 weeks produced 10% to 20% additional functional improvements (ES= 0.80 – 1.90; p< 0.036). Benefits after short and long exercise interventions persisted when compared with baseline, especially in SPPB, gait speed, and Sit-to-stand tests (ES≥ 0.60; p< 0.041). Detraining resulted in a 10% to 25% loss of strength and functional capacity even after 24-week training (ES≥ 0.24; p< 0.039). Article 2 - High to very high intra-session repeatability was found for both the dominant and non-dominant legs (CV≤ 6.0%). Similarly, both legs showed high inter-session repeatability (SEM≤ 0.26 N·kg-1). Furthermore, significant relationships were found between Dominant and Non-dominant IKE tests with Gait Speed and ALM/BMI (r ≥ 0.58). Article 3 – Significant changes (p< 0.01; ES≥ 0.27) in the IKE strength for both the dominant (+0.27 N·kg-1) and non-dominant legs (+0.25 N·kg-1) were produced after the training intervention. Likewise, significant decrements (p< 0.01; ES≥ 0.31) were detected after the inactive period for the dominant (−0.29 N·kg-1) and non-dominant legs (−0.32 N·kg-1). All mean changes were found to be superior to the variability threshold of the IKE test for both legs, with superior sensitivity for the non-dominant leg (≥ 73%). Conclusions: This PhD Thesis suggests that i) the gains in strength and functional capacity after multicomponent training were maintained after short and long inactivity periods in institutionalized older adults with sarcopenia, and ii) the field-based IKE test is a repeatable, suitable, sensitive, and practical assessment tool for lower-limb screening in institutionalized older adults.