Inter-Individual Rapid Force Improvements after Mixed Session and Traditional Periodization in Aging Adults: A Randomized Trial

Background Different periodization models have been widely used to improve maximum and rapid force in aging adults. However, it is unclear if some specific model can influence the remarkable heterogeneity of responsiveness to rapid torque improvements following resistance training.Aims Compare the effects of mixed session periodization (MSP) and traditional (TP) models on neuromuscular performance and individual responsiveness in aging adults.Methods Twenty-two aging men and women (64.6 +/- 5.2 years old; 1.68 +/- 0.1 m; 77.8 +/- 16.0 kg) completed the intervention period. They were assigned into MSP (n = 11) or TP (n = 11) resistance training for lower limbs. The outcome measures normalized dynamic leg press (5-RM: (BM)), absolute and normalized knee isometric peak torque (PT and PT: (BM)) and rate of torque development, and impulse were assessed at baseline and after three blocks of a 9-wk resistance training (3 sessions per week). Thigh leg lean mass was assessed by dual-energy x-ray absorptiometry at baseline and after the intervention.Results Similar increases were observed for 5-RM: (BM) (MSP: 28.8% +/- 13.5% and TP: 26.4% +/- 7.6%, P < 0.001), PT (MSP: 223.7 +/- 50.7 N<middle dot>m and TP: 189.9 +/- 58.6 N<middle dot>m, P < 0.001), but it was not observed for PT: (BM) (MSP: 16.4% +/- 16.5% and TP: 4.7% +/- 9.2%, P > 0.05). Absolute and normalized RTD remained unchanged throughout intervention (P > 0.05), but both groups improved impulse (MSP: 22.1% +/- 25.7% and TP: 12.6% +/- 45.2%, P < 0.001). Only MSP responders (n = 5) presented significant time effect for absolute RTD (P < 0.05) and impulse (P < 0.05).Conclusion Although both periodization protocols increased 5-RM: (BM) and PT, it was not interchangeable through improvements in RTD even adopting power training session. Furthermore, these results suggest a great inter-individual variability following different periodization models for aging people.