Comparison of different periodization models on isotonic and isokinetic muscle strength and lean mass in tactical athletes

Introduction: Tactical athletes need to develop strength and lower limb lean mass (LL LM) to perform effectively. Resistance training (RT) is the most effective way to achieve these goals. Two periodization models stand out: traditional linear periodization (TLP) and daily undulating periodization (DUP). Objective: To verify the effect of lower limb RT with TLP and DUP on isotonic and isokinetic muscle strength and lean mass in tactical athletes. Method: Thirty-five Brazilian Army military (21.57 +/- 2.02 years; 81.81 +/- 11.19 Kg; 177.79 +/- 6.88 cm) were divided into two treatment groups and one active control group. Interventions: The treatment groups performed 9 weeks of supervised RT (18 sessions), consisting of free weight exercises in this order: back squat, squat lunge, deadlift, and stiff legged deadlift. Dynamic isotonic muscle strength, lean mass, and isokinetic knee extension and flexion were assessed at baseline and post treatment period. Results: There was a significant pre-post difference in dynamic isotonic muscle strength (TLP, P < 0.001; DUP, P < 0.001) and lean mass (TLP, P = 0.034; DUP, P = 0.003) of LL LM in both treatment groups. However, effect sizes (ES) and variations (%Delta) of gains were greater in the DUP group both in muscle strength (TLP, ES = 1.55, %Delta = 30.97; DUP, ES = 2.55, %Delta = 36.02), and in lean mass (TLP, ES = 0.13, %Delta = 2.07; DUP, ES = 0.44, %Delta = 2.95). For isokinetic knee flexion strength, a significant difference was found between the TLP versus CON. Conclusion: Both lower limb RT periodization models provided gains in muscle strength and lean mass, with a small advantage for the DUP approach. In the isokinetic knee flexion strength, the TLP was more effective.