Active recovery effects on oxygen uptake and muscle oxygenation during interval swimming

Background: The interval swimming format has been widely used for training in competitive swimming. The recovery conditions of rest period in interval swimming are classified into 2 major categories: active recovery and passive recovery. Although, several studies have shown about passive recovery condition during interval swimming, there were few studies on active recovery conditions. We hypothesized that recovery responses are different between active and passive recovery conditions during interval swimming. Changes in muscle oxygenation during exercise can nowbe evaluated using a near-infrared spectroscopy (NIRS) device; however, no studies have evaluated muscle oxygenation during swimming. Therefore, the purpose of this study was to assess the active recovery effects of on oxygen uptake and muscle oxygenation during interval swimming. Methods: All experimental measurements were conducted using tethered leg kicking. The 11 well-trained male collegiate competitive swimmers performed a graded test and 6 rounds of swimming for 60 s, with 30 s of either active recovery or passive recovery. The tethered load of swimming period and active recovery period were set at maximum oxygen uptake (100% of VO2max) and at 50% of VO2max, respectively. Oxygen uptake was determined using a gas analysis system, while oxyhemoglobin (O2Hb) and deoxyhemoglobin (HHb) levels at the left vastus lateralis muscle were determined using a NIRS device during interval swimming. Blood lactate accumulations were measured at 1, 3, 5 min after each trial completion. Results: Mean value for oxygen uptake during the rest period was higher with active recovery condition than passive recovery condition. In addition, O2Hb variations during rest period for active recovery condition were significantly lower than for passive recovery condition. On the contrary, HHb variations during rest period for active recovery condition were significantly higher than for passive recovery condition. Blood lactate accumulations was not significantly different between recovery conditions. Discussion: Active recovery during interval swimming was associated with higher oxygen uptake response and lower muscular reoxygenation.