Estimating reduced oxygenation levels in the erector spinae lumbar muscle region during seated whole-body vibration

Previous research has demonstrated deficiency in blood supply to lumbar muscles in the form of decrease in oxygenation and blood volume during short duration of exposure to seated whole-body vibration (WBV). However, it is not clear if these WBV-induced lumbar muscle responses are comparable, for example, to that of an endurance exercise-induced oxygenation and blood volume responses?On a separate day, eight healthy participants performed a seated arm cranking exercise until volitional exhaustion. On three separate days, participants were exposed to 3, 4.5, and 6 Hz on a vibration simulator for a period of 16 min. During the fifth minute of WBV ‘with’ and ‘without’ backrest support, participants performed rhythmic handgrip contractions for 1 min. Oxygenation and blood volume responses from the lumbar region were measured utilizing Near-infrared spectroscopy.A percent change in oxygenation and blood volume responses during WBV was expressed as a function of spectroscopy-derived minimum (at the exhaustion) and maximum (during recovery from WBV) responses obtained from the arm cranking exercise. Highest decrease in spectroscopy-derived responses (represented in mean values) was observed: at 4.5 Hz; sitting ‘without’ backrest support; and handgrip contractions during exposure to WBV.Spectroscopy-derived hemodynamic responses obtained during the endurance exercise were significantly lower than the corresponding values measured at different WBV conditions, implying that although the spinal resonance frequency of 4.5 Hz decreases oxygen saturation considerably, progress of oxygen depletion is further evidenced during an endurance exercise.Relevance to industryEstablishing fully oxidized and reduced physiologic states for the lumbar muscle by occluding arterial blood flow is difficult. However, by utilizing an aerobic protocol until volitional exhaustion, lumbar oxygenation and blood volume responses for a variety of WBV-related exposures can be compared. It was concluded that WBV-induced lumbar hemodynamic responses fall well within the reduced and oxidized conditions established through the endurance arm cranking exercise.