Abstract
Muscular fatigue can affect postural control processes by impacting on the neuromuscular and somatosensory system. It is assumed that this leads to an increased risk of injury, especially in sports such as alpine skiing that expose the body to strong and rapidly changing external forces. In this context, posture constraints and contraction-related muscular pressure may lead to muscular deoxygenation. This study investigates whether these constraints and pressure affect static and dynamic postural control. To simulate impaired blood flow in sports within a laboratory task, oxygen saturation was manipulated locally by using an inflatable cuff to induce blood flow restriction (BFR). Twenty-three subjects were asked to stand on a perturbatable platform used to assess postural-related movements. Using a 2 × 2 within-subject design, each participant performed postural control tasks both with and without BFR. BFR resulted in lower oxygenation of the m. quadriceps femoris (p = 0.024) and was associated with a significantly lower time to exhaustion (TTE) compared to the non-restricted condition [F(1,19) = 16.22, p < 0.001, ηp2 = 0.46]. Perturbation resulted in a significantly increased TTE [F(1,19) = 7.28, p = 0.014, ηp2 = 0.277]. There were no significant effects on static and dynamic postural control within the saturation conditions. The present data indicate that BFR conditions leads to deoxygenation and a reduced TTE. Postural control and the ability to regain stability after perturbation were not affected within this investigation.
Highlights
In many sport disciplines, athletes must respond quickly to changes in their environment and alter physical forces to maintain an optimal stance
While relative postural sway is lower in NBFR condition in the first intervals, differences in O2 saturation increase during the course of the measurement with NBFR achieving higher values than blood flow restriction (BFR)
In the dynamic postural control (PC) conditions, time to exhaustion (TTE) was not affected by reduced O2 saturation in the BFR settings
Summary
Athletes must respond quickly to changes in their environment and alter physical forces to maintain an optimal stance. The muscle activity thereby is mainly isometric and eccentric (Hofmann et al, 2001). The resulting disparity between energy demand and consumption leads to muscular fatigue (Sjøgaard et al, 1988; Sutton, 1992; Goodall et al, 2014; Grassi et al, 2015), which is defined as a decrease in muscle contractility and, a loss of performance (Szmedra et al, 2001; Allen et al, 2008; Hettinga et al, 2016). Joint angles, intramuscular forces, and duration of contraction may affect muscular blood flow (Konings et al, 2015). If joint angles of the hip or knee decrease
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