The effects of acute and chronic hypoxic plyometric exercise on post activation potentiation

Abstract

Introduction: In the literature, only acute effects of exercise, mostly combined with plyometrics or blood flow restriction (BFR), have been examined on post activation-potentiation (PAP). Although systemic and local hypoxia have some similar effects, we found only one study (Ramos-Campo et al., 2020) reporting a PAP effect with systemic hypoxia. There is no study investigating chronic effects, and there is also no study examining acute and chronic effects of exercise together, not only in hypoxia but also in normoxia. The aim of this study is to examine the acute and chronic effects of plyometric exercise in hypoxia on PAP, and to test differences between high and low hypoxia. Method: Nineteen team-sports athletes undertook 8 week drop-jump (DJ) training in Low-Hypoxia (LH, n=8), Normoxia (N, n=6), and High- Hypoxia (HH, n=5) using a hypoxicator set using a biofeedback system to sustain a SpO2 of 90%, 97-100%, and 80%, respectively. PAP assessments were applied under both normoxia and hypoxia on different days. Two DJ trials from 40-cm height were obtained as baseline measurements, and then 7.5 min passive rest was given under each group’s hypoxia level. Following 1x5 DJs for pre-test, and 1x8 DJs for post-test as PAP protocol, DJ tests were applied at 2nd and 4th min. Results: RM-ANOVA, to assess acute effect, showed a significant conditionxtest interaction (F=3.40, p=0.044), and only under normoxia condition DJ-height was significantly higher at 2nd (31.7cm) and 4th min (31.6cm) than baseline (30.1cm)(p<0.05). For chronic effect, mixed- ANOVA represented a significant groupxtest interaction (F=2.70, p=0.048). Only HH significantly increased DJ-height from baseline (30.0cm) to 2nd (31.9cm) and 4th min (32.9cm) (p<0.05). Conclusion: We conclude that while acute hypoxia drop jump exercise may damage net balance between potentiation and fatigue which occurred after conditioning activity, high hypoxia drop jump training may affect this balance in favour of potentiation without any condition difference.