Effects of Dryland Training During the COVID-19 Lockdown Period on Swimming Performance

Purpose: To examine the effect of dryland training during an 11-week lockdown period due to COVID-19 on swimming performance. Methods: Twelve competitive swimmers performed 50- and 300-m maximum-effort tests in their preferred stroke and 200-, 400-, and four 50-m front crawl sprints (4 x 50 m) before and after the lockdown period. Critical speed as an index of aerobic endurance was calculated using (1) 50-, 300-, and (2) 200-, 400-m tests. Blood lactate concentration was measured after the 400- and 4 x 50-m tests. To evaluate strength-related abilities, the dryland tests included handgrip and shoulder isometric strength. Tethered swimming force was measured during a 10-second sprint. During the lockdown period, dryland training was applied, and the session rating of perceived exertion training (sRPE) load was recorded daily. Results: sRPE training load during the lockdown was decreased by 78% (16%), and critical speed was reduced 4.7% to 4.9% compared to prelockdown period (P <.05). Performance time in 200, 300, and 400 m deteriorated 2.6% to 3.9% (P <.05), while it remained unaltered in 4 x 50- and 50-m tests (P >.05). Tethered force increased 9% ( 10%) ( P <.01), but handgrip and shoulder isometric force remained unaltered (P >.05). Blood lactate concentration decreased 19% (21%) after the 400-m test and was unchanged following the 4 x 50-m tests ( P >.05). Conclusions: Performance deterioration in the 200, 300, and 400 m indicates reduced aerobic fitness and impaired technical ability, while strength and repeated-sprint ability were maintained. When a long abstention from swimming training is forced, dryland training may facilitate preservation in short-distance but not middle-distance swimming performance.