ECSS Paris 2023: CP-PN08
INTRODUCTION: For athletes, daily condition assessment is important for maintaining exercise performance. Although several markers for the assessment (e.g., exercise performance, scores of subjective feelings, hormones, resting heart rate) are proposed, a factor that affects recovery process is sleep related variables. While body temperature fluctuations may affect diurnal fluctuations in sleep-related hormones such as cortisol and melatonin (Kräuchi., et al., 2006; Hickie et al., 2013), changes in nocturnal body temperature and sleep quality following daily training have not been elucidated sufficiently in endurance athletes. Therefore, the aim of the present study was to investigate the relationship between skin temperature rhythm at the night and sleep parameters in female long-distance runners. We hypothesized that the day with strenuous training would alter nocturnal skin temperature and sleep quality compared to the day without training. METHODS: Eleven female long-distance runners were evaluated skin temperature (proximal site) and sleep parameters for 7 consecutive days. Skin temperature was measured continuously every 5 min by attaching the button-type thermometer on the area of the groin using a seal. Sleep parameters were measured using an actigraphy, including sleep efficiency, total sleep time, sleep latency, and wake time after sleep onset (WASO). During the measurement period, the data were compared between two conditions: a day when strenuous training was conducted (TR) and a day when training was not conducted (REST). RESULTS: The total sleep time in TR was significantly longer than in REST (447.6 ± 60.5 min vs. 360.2 ± 45.3 min; P<0.05). Skin temperature was significantly higher on TR compared with REST at 10 min and 20 min after bedtime (P < 0.05). At 60 min, skin temperature was significantly lower on TR compared with REST (P < 0.05). From 90-130 min, skin temperature was significantly elevated compared with the value of bedtime (P < 0.05). CONCLUSION: The strenuous training affected the body temperature rhythm during night and total sleep time in female long-distance runners.
Read CV Saya OkamotoECSS Paris 2023: CP-PN08
INTRODUCTION: We have previously shown that a reduced pace during the end of a marathon is related to blood muscle damage and inflammation markers, which in turn are associated with the total number of steps taken during the race. We hypothesized that the total load of steps during the marathon might influence these damage and inflammation markers. The aim of this study was to estimate the total load of steps during a marathon and clarify its effect on muscle damage and inflammation. METHODS: Twenty-two healthy non-professional runners (15 men, 7 women, average age 23.2 ± 1.7 years old) who participated in the 43rd Tsukuba Full-Marathon race (Tsukuba-city Japan) were recruited as volunteers. They ran with a GPS watch which has a built-in accelerometer. Stride rate and stride length were obtained from the watch. Serum muscle damage markers (serum creatine kinase activity, etc.), inflammation markers (serum CRP, etc.) as well as muscle soreness were measured before, immediately after, and the one day after the marathon. The distance covered during a 12-minute run was measured beforehand. Additionally, on non-race days, a walking load system was used to measure the load on the soles of the feet at the marathon running speed. The total load was estimated by multiplying the load per step by the total number of steps during the marathon. RESULTS: The ratio of change in pace from the second segment of the marathon (5–10 km) to the final segment (35–40 km) showed a negative correlation with serum creatine kinase (CK) activity. The total load during the marathon showed a positive correlation with finish time of the marathon, body weight, body mass index (BMI), and total number of steps during of the marathon, and a negative correlation with stride length during the marathon and the distance covered during a 12-minute run. In men, the total load during the marathon showed a positive correlation with serum CRP levels one day after the marathon. CONCLUSION: he total load during the marathon is related to body weight and total number of steps during the marathon, and runners with longer stride lengths had lower total loads during the marathon. Runners with high level of total load during a marathon may influence marathon-induced skeletal muscle inflammation. It is suggested that men, who weigh more than women, have a larger total load during the marathon, which may increase skeletal muscle inflammation. Since we measured the load in a fresh state other than race days, it is possible that the load would be higher under the fatigued conditions typical during the marathon itself. This remains a subject for future research.
Read CV Keisuke ISHIKURAECSS Paris 2023: CP-PN08
INTRODUCTION: The metabolic cost (C, J/(kg m)), the energy needed to move one kilogram of body mass along one meter, is an important physiological factor also for performance prediction and monitor. Indeed, according to di Prampero’s model (1) performance velocity is given by the ratio of the oxygen consumption fraction and C. In running, C is speed independent (at least up to 5 m/s), in walking C show a U-shape profile and it becomes higher than running at about the walk-run transition speed (1). Race walking is an Olympic discipline of the athletics since the early ‘900. It is supposed to be a walk, by the rule, although performed at speeds typical of running (3.5-4.5 m/s) (2). The aim of this study was to compute race walking C as a function of speed. METHODS: Eight international-level race walkers (5 men: 1h20’48”±2’51” 20 km PB, with the Olympic champion; 3 women: 1h33’15”±2’50” 20 km PB) were asked to race walk at increasing speed steps (3.2-4.4 m/s) for 4 minutes, while gas exchanges were collected by a metabolic cart. C was calculated as the net oxygen consumption multiply by energy equivalent of oxygen and divided by race walking speed. Linear hierarchical regression analyses were performed adopting the speed as independent variables and C as dependent variable. RESULTS: C increased as a function of speed in all athletes, although with different slopes and intercepts. The linear mixed-effect model with random intercepts for speed nested within subjects showed a significant main effect of speed (β=0.732; SE=0.084; F=75.3; P<3.0×10^-10) explaining 93.7% of the variance (conditional R^2=0.937). The C vs. speed relationship can thus be described by this linear equation: C = 0.73×v +2.15 (with v in m/s). CONCLUSION: Race walking Cost is higher than running at each speed, and the difference increases as a function of speed. It is also higher than walking, but the slope is lower than the extrapolated walking parabolic profile. Albeit the adherence to the rule, C can be a determinant for the maximal race walking speed that can be sustained during an official (aerobic) competition: with 65 ml/(kg min) of oxygen consumption, a top speed of about 4.3 m/s can be reached by race walking, whereas it would be almost 5.8 m/s by running. REFERENCES: 1) di Prampero, Int J Sports Med, 1986 2) Pavei et al, Eur J Sports Sci, 2014
Read CV Gaspare PaveiECSS Paris 2023: CP-PN08