Category: Applied Physiology

Men clearly outperform women in athletic events that require moving their body through space. However, the magnitudes of the difference varies by event. For Olympic running events men run 10-12% faster than women in events ranging from 100 meters to the marathon. In contrast, for the high jump men outperform women by nearly twice the running offset (20%), and in the conventional countermovement jump the sex difference is greater yet at 25%. These observations suggest an interaction between event mechanics and bodily differences between males and females. Running differences are well explained by close alignment between the additional proportion of the female body comprised of fat (+10%) with the 11% difference in performance. However, it is unclear why jumping performance differences are so much greater. Jumping differs from running in that performance depends largely on a single powerful contraction on take-off. Here, we evaluated the possibility that due to the mechanical differences between running and jumping, sex differences in height also factor into the sex difference in jumping performance. Results to date suggest that sex differences in height and body composition do account for the male-female jump differences. Therefore we conclude that sex differences in athletic performance are set by an interaction between bodily differences and mechanical demands of the event.

Multiple Sclerosis (MS) is an autoimmune disease associated with increased cardiovascular risk. Greater resting beat-to-beat blood pressure variability (BPV) is a known predictor of cardiovascular risk. Therefore, we hypothesized that resting beat-to-beat BPV is increased in individuals with MS compared to matched healthy controls. In 7 patients with relapsing-remitting MS (2 males) and 7 sex-, age-, and weight-matched healthy controls, beat-to-beat blood pressure (Finometer) was recorded during 10 minutes of quiet supine rest. Individuals with MS had similar resting mean blood pressure (BP) compared to healthy controls (P= 0.736), however the BP standard deviation (SD) and coefficient of variation (CV) was less in MS (BP SD; MS: 3.2 +/- 0.2 vs. CON: 4.0 +/- 0.2, P=0.022 and BP CV; MS: 3.8 +/- 0.3 vs. CON: 4.7 +/- 0.2, P=0.025 ). Similarly, mean resting systolic blood pressure (SBP) was not different between MS and healthy controls (P=0.207) but the SBP SD and CV was less in MS (SBP SD; MS: 4.7 +/- 0.4 vs. CON: 6.6 +/- 0.5, P=0.013 and SBP CV; MS: 4.3 +/- 0.4 vs. CON: 5.8 +/- 0.4, P=0.033). In contrast, there was no difference in the DBP SD or CV between the two groups (P= 0.321 and P=0.295; respectively). Contrary to our hypothesis, individuals with MS exhibited reduced resting beat-to-beat BPV compared to healthy controls which may be related to altered autonomic function.