Postural Control Variation in the Single Leg Anterior Reach

Abstract

The single leg anterior reach (SLAR) is often used to assess dynamic postural control. However, the SLAR has yet to undergo a balance plate assessment of postural control that may yield information on the movement coordination strategy utilized during the SLAR. The goal of this study is to examine the effect of different postural control strategies utilized to complete SLAR. Subjects included 31 male professional lacrosse athletes (26.7±2.87 years, 1.82±0.07 m, and 89.7±11.1 kg) and 15 NCAA Division 1 female volleyball athletes (19.4±1.15 years, 1.82±0.08 m, and 75.6±7.6 kg) who performed balance plate instrumented SLAR measurements. Center of pressure (CoP) position data were collected during each trial via a portable balance plate and the CoP excursion (CoPE) for each trial was calculated. CoPE was dichotomized into high (greater movement variability) and low (lower movement variability). Between group t-tests were performed between high vs. low CoPE groups to assess normalized reach distance between movement strategy with an alpha level set at .05. Reach distance was significantly higher in those with higher CoPE in the frontal plane (Left: 62.22±3.90 cm high excursion (HE), 60.96±4.07 cm low excursion (LE), Right: 62.32±3.87 cm HE, 60.86±4.07 cm LE) and total CoPE for the right leg (61.92±5.46 cm for HE and 59.87±4.27 cm for LE). Reach distance was greater in those with higher CoPE in the sagittal plane (Left: 63.45±4.27 cm HE, 59.73±2.68 cm LE, Right: 62.39±5.56 cm HE, 59.40±3.82 cm LE) and total CoPE for the left leg (62.32±3.87 cm for HE and 60.86±4.07 cm for LE). Increased frontal plane movement variability during a sagittal reach SLAR task resulted in greater reach performance. These findings may have clinical implications for individuals demonstrating a lack of movement variability in the frontal plane resulting in lower sagittal plane reach distances. Improvements to frontal plane movement variability strategies may result in increased dynamic postural control.