Date of Award

5-14-2023

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Exercise Science

Advisor(s)

Tom Brutsaert

Keywords

Hypoxic training, RSH Training, Swimming, Swimming ergometer, Wingate Test

Abstract

For over fifty years, athletes have attempted to induce additional improvements in middle and distance race performance by supplementing their sea-level conditioning programs with hypoxic training to improve aerobic capacity. The apparent success of this practice fostered an interest in applying hypoxic training to improve single-sprint, repeated sprint, and team sports performance. In response to this interest, a novel hypoxic training approach, referred to as repeated sprinting in hypoxia (RSH), was proposed. RSH training is similar to training in normoxia (RSN). Both consist of performing multiple short sprints (≤ 30 seconds) on a work-to-rest ratio that does not permit complete recovery. The sole difference between them being the fraction of inspired oxygen (FiO2) during training. RSN training takes place in normoxia (FiO2 = 20.93 %), while during RSH training, the FiO2 is between 13.0% to 15.5%. To date, some evidence in the scientific literature suggests that RSH training induces small to moderate additional improvements in performance compared to the equivalent training in normoxia (RSN); however, there is contrasting evidence that postulates no additional performance improvements occur following RSH training. PURPOSE: The primary purpose of this dissertation was to determine if RSH training stimulated additional improvements in anaerobic capacity and swimming performance compared to the equivalent RSN training. HYPOTHESIS: We hypothesized that the increased hypoxic stress during RSH training, compared to the equivalent RSN training, would induce additional improvements in anaerobic capacity and swimming performance. METHODS: A randomized, single-blind, crossover design was used to train 12 Division II college swimmers from the same team. The twelve enrolled participants were 19.6 ± 1.4 years old, weighed 78.7 ± 10.6 kg, and measured 182.3 ± 6.9 cm in height. The study consisted of two 24-day training blocks separated by a 3-week washout period. All participants completed 7 RSH workouts, or 7 RSN workouts, over each of the 24-day blocks, crossing over after the washout. Each workout included two sets of 8 x 20-second maximal effort sprints, on a 1-minute interval, with 2 minutes of passive rest between sets. Workouts consisted of two sets of repeated sprinting on the bicycle ergometer and two sets on the swimming ergometer with 5 minutes of passive rest between exercise modalities. During RSH training, the FiO2 was 14.4 ± 0.2% maintained in an Altitude Chamber by replacement of O2 with N2 using Hypoxico Systems high flow hypoxic generators (Hypoxico Inc., NY, NY). RSN training was in ambient room air at 20.93% O2 dry and atmospheric conditions of Syracuse, NY. The hypoxic stress during each workout was estimated from arterial oxygen saturation (%SpO2) data collected using a forehead sensor. Training intensity was estimated from the average workload and peak heart rate achieved during each workout. Swimming performance was assessed with a 100-yard swimming time trial and an in-the-water repeated sprint test. Anaerobic capacity was estimated from laboratory-based tests that included a Wingate anaerobic test performed on a cycle ergometer (WAnT) and a novel modified Wingate test performed on a swimming ergometer (WAnT-Swim). Peak power (PP), mean power (MP), low power (LP) and the fatigue index (FI) were measured. In addition, peak heart rate (bpm) was measured during the WAnT and WAnT-Swim, and peak lactate (mmol·L-1) was assessed six minutes after the tests. RESULTS: Training intensity quantified as the mean power maintained during the workout, expressed as a percentage of the respective pre-training Wingate mean power score, did not differ significantly for simulated swim repeated sprinting during RSH (64.2 % ± 11.0%) vs. RSN (73.% ± 20.8%). Correspondingly, during repeated sprint cycling, the training intensity during RSH (19.5% ± 1.6%) was almost identical to RSN training (19.9% ± 1.3). In addition, peak heart rate during simulated swim RSH (138 ± 11bpm) vs. RSN (142 ± 14bpm) were not significantly different, nor were they between hypoxic conditions during cycling, RSH (165 ± 11bpm) vs. RSN (170 ± 11). The hypoxic stress quantified as %SpO2¬ was the only apparent difference between hypoxic training conditions during simulated swim training, RSH (84.2% ± 2.2%) vs. RSN (92.5% ± 2.8%) and cycling, RSH (83.3% ± 2.2%) vs. RSN (95.6% ±0.8%). The main findings of this study were 1) RSH training significantly improved 100-yard time trial by 0.6 seconds (p < 0.05); however, following RSN training, there was a nonsignificant 0.31second increase (slower) in 100-yard performance. 2) Following RSH and RSN training, measures of repeated sprint swimming performance improved significantly (p < 0.05). 3) Following RSH and RSN training, anaerobic capacity based on WAnT and WAnT-Swim performance improved significantly (p < 0.01). 3) Compared to the equivalent RSN training, the increased hypoxic stress during RSH training did not induce additional improvements in swimming performance or anaerobic capacity. CONCLUSION: Therefore, including a land-based, swim-specific repeated sprint training program in the yearly conditioning program of college swimmers may be beneficial. However, until further research establishes that RSH training stimulates additional improvements in swimming performance and anaerobic capacity, RSN training is the pragmatic and cost-effective option.Keywords, hypoxic training, swimming ergometer, WAnT, WAnT-Swim, repeated sprints in hypoxia.

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