Influence of Menstrual Cycle or Hormonal Contraceptive Phase on Physiological Variables Monitored During Treadmill Testing

Purpose: To examine the influence of menstrual cycle (MC) and hormonal contraceptive (HC) cycle phases on physiological variables monitored during incremental treadmill testing in physically active women (eumenorrheic, EUM = 16 and monophasic HC-users, CHC = 12).Methods: Four running tests to exhaustion were performed at bleeding, mid follicular (mid FOL)/active 1, ovulation/active 2, and mid luteal (mid LUT)/inactive. HC and MC phases were confirmed from serum hormones. Heart rate (HR), blood lactate (Bla), and V˙O2 were monitored, while aerobic (AerT) and anaerobic (AnaT) thresholds were determined. V˙O2peak, maximal running speed (RUNpeak), and total running time (RUNtotal) were recorded.Results: No significant changes were observed in V˙O2 or Bla at AerT or AnaT across phases in either group. At maximal effort, absolute and relative V˙O2peak, RUNpeak, and RUNtotal remained stable across phases in both groups. No significant fluctuations in HRmax were observed across phases, but HR at both AerT and AnaT tended to be lower in EUM than in CHC across phases.Conclusion: Hormonal fluctuations over the MC and HC do not systematically influence physiological variables monitored during incremental treadmill testing. Between group differences in HR at AerT and AnaT underline why HR-based training should be prescribed individually, while recording of MC or HC use when testing should be encouraged as phase may explain minor, but possibly meaningful, changes in, e.g., Bla concentrations or differences in HR response.

Validity of Trunk Acceleration Measurement With a Chest-worn Monitor for Assessment of Exercise Intensity

Background: Recent advancements in wearable technology has enabled easy measurement of daily activities, which can be applied in rehabilitation practice for the purposes such as maintaining and increasing the activity levels of the patients. A smart clothing system is one of the newly developed wearable systems that enables the measurement of physical activity such as heart rate and/or acceleration. In this study, we aimed to examine the validity of trunk acceleration measurement using a smart clothing system (‘hitoe’ system) in assessing the physical activity, which was measured using the expiratory gas analysis. Methods: Twelve healthy individuals participated in the study. The trunk acceleration was simultaneously measured using a triaxial accelerometer embedded in a smart clothing activity monitoring system (‘hitoe’ system), and the percent VO2 reserve (%VO2R) was determined by performing expiratory gas analysis during treadmill testing. Three parameters, that is, moving average (MA), moving standard deviation (MSD), and moving root mean square (RMS), were calculated using the norm of the trunk acceleration. The relationships between these accelerometer-based parameters and %VO2R from expiratory gas analysis for each individual were examined. Results: The values of MA, MSD, RMS, and %VO2R were significantly different between levels 1, 2, 3, and 4 in the Bruce protocol (P<0.01). The average coefficients of determination for individual regression for %VO2R vs. MA, %VO2R vs. MSD, and %VO2R vs. RMS were 0.89±0.05, 0.96±0.03 and 0.91±0.05, respectively. The parameters based on the trunk acceleration measurements were significantly correlated with %VO2R and activity levels. Among the parameters examined, MSD showed the best correlation with %VO2R, indicating high validity of the parameter for assessing physical activity. Conclusions: The present results support the validity of the MSD calculated from the trunk acceleration measured with a smart clothing system in assessing the exercise intensity.Trial registration: UMIN000034967Registered 21 November 2018 (retrospectively registered).

Initial Results From SOMMA: Contribution of Mitochondrial Function to Walking and Fitness

We hypothesize that the capacity of mitochondria in quadriceps skeletal muscle to generate ATP energy by respirometry (OXPHOS) in biopsies from the vastus lateralis, and in whole quadriceps muscle by 31PMRS (ATPmax) would contribute to 4 and 400m gait speed and to peak oxygen consumption on treadmill testing (VO2peak). In analyses from the first SOMMA participants recruited (N=122), OXPHOS was similarly associated with 4m (r=0.21) and 400 m (r=0.21) walking speed (P&lt;0.01). However, ATPmax was not associated with either 4m or 400m walking speed (r=-0.02 and -0.07 respectively). In contrast both OXPHOS (r=0.43) and ATP max (r=0.35) were more strongly correlated with fitness (VO2 peak). These findings suggest that in older people, the mitochondrial capacity to generate ATP plays an important role walking speed and may be even more important to fitness.

P.082 The Toronto Concussion Study: The Feasibility and Effects of Early Prescribed Aerobic Exercise on Recovery and Post-Concussive Symptoms in Adults – A Pilot Study

Background: Evidence suggests that aerobic exercise (AE) soon after concussion may facilitate earlier recovery in athletes. The purpose of this pilot study was to investigate the feasibility and effects of early sub-symptom threshold AE on symptom trajectory and recovery time in a heterogeneous adult population. Methods: Adults presenting within 7 days of concussion were randomized to either the experimental group: prescribed AE (90% of symptom-limited heartrate achieved on Buffalo Concussion Treadmill Test [BCTT]), 30 minutes/day, 5 days/week, or the control group: standard of care exercise recommendations. Participants were assigned a heartrate monitor bracelet to track activity. They underwent serial treadmill testing to monitor exercise tolerance, update prescriptions and determine recovery. Results: 20 participants (10 per arm) completed the BCTT protocol within 7 days of injury, with 8/20 demonstrating exercise tolerance at week 1. 66% (4/6) of those in the experimental group were recovered by week 4, compared to only 43% (3/7) in the control group. Average heart rate monitor compliance was 32% of the prescribed time among all participants, and self-reported exercise prescription compliance was 43% in the experimental group. Conclusions: Early post-concussion aerobic exercise in the general adult population is a promising intervention; this study will inform the design of a larger trial.

Comparison of Aerobic and Muscular Power Between Junior/U23 Slalom and Sprint Paddlers: An Analysis of International Medalists and Non-medalists

This study aimed to compare the aerobic power (treadmill running) and muscle power (bench press and bench pull) of Junior/U23 paddlers from Slovakia who won medals in international championships with that of those who did not take the podium. Forty-three Slovak Junior/U23 paddlers (sprint = 24, medalists = 8, non-medalists = 16; slalom = 19, medalists = 11, non-medalists = 8) were tested in 2018 and 2019 after the world championships. The maximal oxygen uptake (VO2max) and the velocity at maximal oxygen uptake (vVO2max) were determined by the incremental running protocol (0% slope and 1 km⋅h–1 increments every minute until volitional exhaustion). Mean maximal power from the entire concentric phase was recorded during bench press and bench pull exercises by the validated TENDO weightlifting analyzer. No interaction was obtained between medal and canoe discipline for VO2max (p = 0.069, F = 3.495), vVO2max (p = 0.552, F = 0.361) and absolute (bench press: p = 0.486, F = 0.495; bench pull: p = 0.429, F = 0.640) or relative (bench press: p = 0.767, F = 0.089; bench pull: p = 0.696, F = 0.155) mean maximal power. Conversely, a significant effect for the medal on the bench press (absolute p = 0.017, F = 6.170; relative p = 0.043, F = 4.384) and the bench pull (absolute p = 0.041, F = 4.470) mean maximal power were observed. Our study indicates the absolute mean power on the bench press as a prerequisite for success in international Junior/U23 championships of slalom and sprint canoeing. However, the mean power on bench pull seems to have a deeper influence on sprint paddlers when compared to slalom athletes. Regarding the aerobic power, the data from the treadmill testing did not reveal outcomes between medalists and non-medalists. This result can be associated with the lack of specificity of the incremental treadmill testing for canoeing, and future studies are encouraged to propose specific protocols to compare the aerobic power of medalists and non-medalists in international slalom and sprint championships.