Soccer is the most popular sport worldwide, with over 265 million participants. Soccer is unique in that the ball can be directed deliberately and purposefully with the head, an act referred to as ‘heading’. In recent years, there has been concern about the association between repetitive subconcussive head impacts associated with heading and chronic traumatic encephalopathy. Heading causes immediate changes in biochemical and electrophysiological markers of traumatic brain injury, and some studies have reported brain structural changes and dysfunction in former soccer players. In 2019, it was reported that the mortality associated with neurodegenerative diseases was about 3.5 times higher among former professional soccer players. Following that, in early 2020, the guidance have been published to limit heading by age in some regions including England and Scotland. In this review, we will expound the immediate and long-term effects of heading associated with chronic traumatic encephalopathy and the measures that should be taken into consideration in the practice of soccer instruction, based on the latest findings.
This study aimed to elucidate the effects of exercise intensity on stretch-shortening cycle (SSC) function of the lower limbs after cycling. Ten male triathletes performed a cycling graded test to determine the ventilatory threshold (VT) and two hopping-cycling (30 min of cycling at 90 or 110% VT)-hopping tests. The two hopping-cycling-hopping tests performed in random order. Power output (PO), heart rate (HR) and rate of perceived exertion (RPE) were monitored throughout the 30-min cycling. Blood lactate concentrations (BLa) were measured in order to assess metabolic stress. The SSC function was calculated as the ratio of the jump height to the time spent in contact with the ground (reactive strength index [RSI]). PO, HR and RPE values during cycling at 110%VT was higher than at 90%VT (p < 0.01). BLa value after the cycling at 110%VT was higher than at 90%VT (90%VT: 2.4±1.0 vs. 110%VT: 5.9±2.8 mmol/L, p < 0.01). Regardless of the cycling exercise intensity, the RSI significantly decreased after the cycling exercise (p < 0.01). The RSI remained decreased at 15 min after the cycling exercise (p < 0.05). These results demonstrated that the SSC function decreased after cycling. Exercise intensity during cycling is likely to have no effect on the decrease in SSC function.
The aim of this study was to investigate longitudinal changes in rate for development (RFD) during the early, late, and whole phases, and to determine whether early RFD is exhibited in response to the improvement of explosive force production in training throughout the competitive season. Fifteen male jumpers participated in personal training according to the training cycle (Semi-annual two-cycle periodization model) of their team. The early, late and average RFD along with peak force during isometric single-leg press with a knee angle of 115° were measured. The measurement was performed during the pre-season (January or March) and post-season (September or November). Based on comparison between the two measurements, it was found that 10 participants displayed improved performance in the major jump event. The average RFD increased significantly for all participants (p = 0.02, d = 0.67). Participants who achieved their personal best had seen a significant increase in early RFD (p = 0.03, d = 0.84). In the contrast, late RFD (all participants; p = 0.06, d = 0.54, participants who achieved personal best; p = 0.07, d = 0.65) and peak force (all participants; p = 0.31, d = 0.27, participants who achieved personal best; p = 0.15, d = 0.50) did not show significant changes. These results suggested that changes in early, late, and average RFD varied respectively. Moreover, early RFD was found to be the best indicator that reflects improved jumping performance through explosive force production compared to late RFD, average RFD, and peak force.
The purpose of this study was to examine the effects of a six-month Square-Stepping Exercise (SSE) program on physical fitness and cognitive function in elderly and the effects of differences in cognitive function levels before the program on cognitive function. Twenty-four elderly (≧75 years old, mean age: 80.7±3.8 years) participated in the SSE program (once a week, 90 minutes/session, for six months). Grip strength, single leg balance with eyes open, chair stand, figure-8 walking test, and cognitive function (Five Cog) were measured before and after the program. Physical function did not improve during the SSE program. Significant memory and language improvements in Five Cog were observed. There was no significant interaction between the pre cognitive function level and the pre results. In conclusion, the six-month SSE program is an effective exercise for improving memory and language in cognitive function of elderly women and prevented physical function decline. However, there was no difference in the improvement due to the pre cognitive function level.
In mammals, the circadian rhythms have been shown to regulate several physiological functions, including body temperature, sleep-wake behavior, physical activity, hormonal secretions, and metabolism. These processes are controlled by circadian clock genes, and abnormal circadian rhythms are associated with the development of obesity, diabetes, and lifestyle-related diseases. In addition, the timing of behaviors such as food intake, exercise, and stress influence circadian rhythms, including clock gene expression in peripheral tissues. Therefore, the interaction between nutrition and the circadian clock is so-called “chrono-nutrition” is poised to become an important research field of chronobiology. In this review, we review the effects of a timed-nutrition on circadian clocks and their timing-dependent effects on physiological functions.