Enhanced gait following NW-RSA training links to reduced myostatin and improved L-arginine metabolites in older women with preserved vitamin D.

Thirty women (age = 68.9 ± 6.04 years), with preserved vitamin D status and sedentary lifestyle, participated in the study, the aim of which was to evaluate the effects of Nordic walking training with additional loading (NW-RSA), on gait quality, muscle mass, and physical fitness in relation to changes in selected exerkines and nitric oxide metabolites. The training was conducted three times a week, for 12 weeks. All indicators were assessed before and after the intervention. Blood samples were collected at baseline, post-12 weeks, and 1 hour after the first and the last NW-RSA training session. NW-RSA induced significant enhancements in gait control, manifesting as increased walking cadence (3%), speed (6%), and step length (3%), and reduced step time (6%) (p<0.05). The improvement in muscle strength (isokinetic knee extension strength: peak torque (10%), total work (11%), and average power (18%) (p<0.01), and physical fitness (p<0.01) was registered. Those changes were accompanied by significantly decreased myostatin (18%, p<0.05) and carboxylated osteocalcin (15%, p<0.01) levels. The L-arginine concentration and L-arginine/ADMA ratio were increased (respectively 8% and 7%, p<0.05) post-training period. The first session of NW-RSA increased L-arginine concentration (18%, p<0.01) and decreased methylarginine (37%, p<0.01), and the last reduced the pro-inflammatory IL-18 (18%, p<0.01) and carboxylated osteocalcin (4%, p<0.05). NW-RSA training improved gait quality, muscle strength, and physical fitness in elderly women. These enhancements were associated with modifications in myostatin levels, the L-arginine/ADMA ratio, and carboxylated osteocalcin concentrations, all of which support muscle adaptive changes.