DYNAMIC BALANCE FOLLOWING SIX MINUTES OF BRISK WALKING IN FEMALES: PRELIMINARY FINDINGS

Esther Steingold, Lacy Harper, Melanie Antonio, William Reed, Valentina Taddia, Breanna McDonald, Micah Poisal, Kaden Buford, Garrett Hester. Kennesaw State University, Kennesaw, GA. BACKGROUND: Research examining balance after fatigue tends to employ strenuous or sustained exercise. Albeit informative, we felt it important to examine responses to activity more closely resembling acts of daily living. In addition, it is critical yet less prevalent to assess dynamic balance as it better represents challenges to postural stability encountered in daily life. The purpose of our ongoing study is to determine the differences, if any, for responses in dynamic balance after brisk walking in young and middle-aged females. Here, we report on preliminary findings based on participants completed to date. METHODS: Four untrained, females (31.5 ± 17.7 yrs) completed a testing visit 3-7 days following a familiarization session. Dynamic balance testing was conducted using a Biodex Balance System before and 2, 6, and 10-min after a 6-min brisk walking task. Balance testing was 30-sec in duration and involved a progressively unstable platform. Postural stability index, indicative of changes in center of gravity, and the standard deviation for this measurement were calculated for multiple planes of movement. The instructions of the walking task were to “cover as much distance as possible”. Friedman’s test and relative changes were computed to examine responses across time. RESULTS: No significant changes were noted for any measures (p=0.091 - 0.380), though the 65% increase in anterior/posterior postural stability index (i.e., more postural sway) was notable. CONCLUSIONS: These preliminary findings suggest that dynamic balance is not negatively affected after a brisk 6-min walk, but interpretation is limited due to our small sample size which resulted in underpowered analyses. Nonetheless, as our sample size increases and age-related comparisons are feasible, it will be of particular interest to determine if these preliminary findings remain consistent in females 45-60 yrs of age

EFFECTS OF A BRISK 6-MINUTE WALK ON NON-LOCAL PERFORMANCE FATIGUE: PRELIMINARY FINDINGS

Kaden Buford, Lacey Harper, Melanie Antonio, William Reed, Valentina Taddia, Breanna McDonald, Micah Poisal, Esther Steingold, Garrett Hester. Kennesaw State University, Kennesaw, GA. BACKGROUND: Non-local fatigue can be described as performance decrements occurring for a muscle group that was not directly involved in the fatiguing activity that preceded. Little evidence exists on non-local fatigue derived from activities mimicking acts of daily living. Determining whether non-local fatigue exist following brisk walking is worthwhile, and rate of torque development (RTD) is a candidate parameter that might possess increased susceptibility. The purpose of our ongoing study is to determine the responses, if any, for maximal and rapid torque production of the upper body after brisk walking in young and middle-aged females. Here, we report on preliminary findings based on participants completed to date. METHODS: Four untrained, females (31.5 ± 17.7 yrs) completed a testing visit 3-7 days following a familiarization session. Subjects completed handgrip testing before and 3, 9, and 11 minutes after a 6-min brisk walking task. The instructions for the walking task were to “cover as much distance as possible”. Subjects were instructed to squeeze the handgrip dynamometer as “hard and fast as possible”. PT, and peak, early (0-50 ms), and late (0-200 ms) RTD were calculated from the torque-time curve. Friedman’s test and relative changes were computed to examine responses across time. RESULTS: PT (-2%; p = 0.960) nor any RTD measures (p \u3e 0.05; -5% ─ +8.5% were reduced after brisk walking. CONCLUSIONS: These preliminary findings suggest that brisk walking does not cause non-local fatigue for the upper body, but interpretation is limited due to our small sample size which resulted in underpowered analyses. As our sample size increases and age-related comparisons are feasible, a primary aim is to determine if these preliminary findings remain consistent in females 45-60 yrs of age since brisk walking may be more demanding in this age group

EFFECTS OF A BRISK 6-MINUTE WALK ON MAXIMAL AND RAPID TORQUE PRODUCTION IN FEMALES: PRELIMINARY FINDINGS

William Reed, Lacey Harper, Melanie Antonio, Valentina Taddia, Breanna McDonald, Micah Poisal, Kaden Buford, Esther Steingold, Garrett Hester. Kennesaw State University, Kennesaw, GA. BACKGROUND: Research examining balance after fatigue tends to employ exercise that is strenuous or specific to an isolated joint. Albeit informative, we felt it important to examine responses to activity more closely resembling acts of daily living. The plantar flexors are particularly susceptible to fatigue derived from walking due to their relatively large contribution compared to more commonly studied muscles of the thigh. In addition, rate of torque development (RTD) is thought to be more sensitive to fatigue than peak torque (PT). The purpose of our ongoing study is to determine the differences, if any, for responses in maximal and rapid torque production after brisk walking in young and middle-aged females. Here, we report on preliminary findings based on participants completed to date. METHODS: Four untrained females (31.5±17.7 yrs) completed a testing visit 3-7 days following a familiarization session. Subjects performed rapid, maximal voluntary isometric contractions of the plantar flexors before and 2.5, 6.5, and 10.5 min after a 6-min brisk walking task. The instructions for the walking task were to “cover as much distance as possible.” PT and rate of torque development at peak (RTDPK), early (0-50 ms and 0-100 ms (RTD0-100)), and late (0-200 ms) time phases were calculated from the torque-time curve. Friedman’s test and relative changes were computed to examine responses across time. RESULTS: Notable, but non-significant, relative decreases were found for RTD0-100 (-41%; p=0.068) and RTDPK (-29%; p=0.058), whereas PT (+5%; p=0.682) and other RTD measures (p\u3e0.05) were unaffected. CONCLUSIONS: These preliminary findings suggest early RTD is more sensitive than later RTD and PT to walking-induced fatigue, but interpretation is limited due to our small sample size which resulted in underpowered analyses. An impaired rate of muscle activation by the central nervous system is one possible explanation for the fatigue-related decrease in early RTD. Nonetheless, as our sample size increases and age-related comparisons are feasible, a primary aim is to determine if these preliminary findings remain consistent in females 45-60 yrs of age. Information gained from the future analysis will elucidate the importance of maintaining rapid torque production in middle-age