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Balance Control of the Movement Initiation on Different Directions in the Star Excursion Balance Test
Get PDFBalance control is an essential skill for human activities. Gait initiation is a common daily movement involved in walking, stepping, and reaching tasks (Halliday et al., 1998). In the gait initiation process, both static and dynamic balance control ability are being tested. Anticipatory postural adjustments (APAs) are the body’s preparation before voluntary movement to maintain balance control. APAs allow for better performance in the subsequent voluntary movement by making a successful transition from static to dynamic balance control (Gribble et al., 2012). The star excursion balance test (SEBT) is a popular functional movement test for balance control. The SEBT involves multi-directional balance control and reaching initiation providing an ideal test for studying APAs in multidirectional reaching movements. Since the study of APAs in multidirectional reaching is lacking in published research, the purpose of this study is to explore the relationship between SEBT reaching directions, APA patterns, center of force (COF) directional displacement, and reaching performance. The difference between reaching directions and limb is also examined.
Ten participants (age: 19.33 ± 1.16 years; height: 169.25 ± 12.88 cm; body mass: 71.18 ± 16.00 kg) performed three complete SEBT trials in each of the anterior (ANT), posteromedial (PM), and posterolateral (PL) directions with both left and right limb stance. The results showed a consistent COF trajectory pattern in each direction and common features across all directions during the S1 APA phase. The S1 APA phase is the 1st phase of the APAs during which the COF shifts posteriorly from the center towards the reaching limb as a countermovement to the impending reach. In the S2 phase, the 2nd phase of the APAs, the COF consistently shifted with mediolateral movement from the reaching limb to the stance limb. The only difference in S2 phase across directions was an anterior component that appeared in the ANT reach but was absent in the PM and PL reaches. Objective results revealed significant differences in reaching distance (RD) between directions (F (2,18) = 48.674, p\u3c .001, partial η2=.844) but not limbs (F (1,9) =1.168, p = 0.308, partial η2=.115). RD in PM was larger than PL and larger than ANT reach. Despite differences in RD, similar COF trajectory patterns were observed across reach directions. There was insignificant difference in anteroposterior displacement (DyS1) between directions (F (2,18) =2.050, p = .158, partial η2=.186) and limbs (F (2,18) = 0.114, p = .743, partial η2=.013). There was significant difference in mediolateral displacement (DxS1) between limbs (F (2,18) = 52.494, p \u3c .001, partial η2 = .854) because of the reaches occurring in opposite directions, left and right, but the magnitude of movement was insignificant (F (2,18) = 1.113, p = .319, partial η2 = .110). The difference in mediolateral displacement (DxS1) between reach directions was insignificant (F (2,18) = 2.652, p = .098, partial η2 = .228). A smaller COF displacement in the reaching tasks of this study compared to the stepping tasks studied by Inaba et al. (2020) show that a reduced magnitude of destabilization is necessary for controlling momentum during the APAs of a reaching task which requires the COF to stay within the base of support
The Effect of Sprint Interval Duration and Training Frequency on Vo2max
Get PDFPurpose: The purpose of the present study was to further identify the lowest effective cycling interval sprint duration and training frequency that improve VO2max. Affective and cognitive measures across different training programs were also examined to inform the feasibility and expected subjective responses to these protocols. Methods: Due to the COVID-19 Pandemic, the original methods of the study were not able to be completed. Instead, data from Towards the minimal amount of exercise for improving metabolic health: beneficial effects of reduced-exertion high-intensity interval training (Metcalfe et al., 2012) and Changes in aerobic capacity and glycemic control in response to reducedexertion high-intensity interval training (REHIT) are not different between sedentary men and women (Metcalfe et al., 2016) were obtained with the authors’ permission to assess the effect of cycling resistance on VO2max. Data Analysis: Data from the two studies were analyzed using an independent t-test to compare changes in VO2max after training against resistances of 5.0 and 7.5% of subjects body mass. Results: There was no significant difference between the percent change in VO2max following training at the two workloads (p = 0.750). Conclusion: The original research question remains unanswered; however, future research examining the physiological, metabolic, and psychological effects of the variety of training parameters involved with interval training is warranted
