The Effects of Mornıng and Evenıng Runnıng on Respıratory Functıon and Lower Extremıty Strength in Pre-Adolescent Male Footballers

The Effects of Mornıng and Evenıng Runnıng on Respıratory Functıon and Lower Extremıty Strength in Pre-Adolescent Male Footballers Coşkun YILMAZ, Süreyya Yonca SEZER, Özgür EKEN, Baha Engin Çelikel ABSTRACT The objective of this study was to examine the impact of eight weeks of morning and evening running on lower extremity strength and respiratory function in 10-12-year-old male soccer players. The participants visited the laboratory 3 times with 1-day intervals before and after the training. The measurements included maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC) and the FEV1/FVC ratio, agility and functional performance tests (FPTs) for the dominant and nondominant legs. The results of our study indicated that morning running was more effective than other forms of exercise in developing the respiratory system. The greatest improvement in FVC, FEV1, MIP, and MEP values was observed in those who performed morning runs (p< 0.001). The findings of investigators study indicate that morning running is more effective than running the dominant leg in a series of lower extremity strength tests, including the single leg (SL) and triple leg (THD) crossover hop for distance tests (CHDs) and the 6 m timed-hop test (6 m THT). The results were statistically significant (p=0.000). With respect to the nondominant leg, the SL and 6-meter THT tests were more effective in the morning running group than in the evening running group (p=0.000). The morning running group had better agility performance than the evening and control groups did. As a result, it was determined that morning jogging had a positive effect on respiratory muscle strength, respiratory function and lower extremity strength in children.

Keywords: Lower extremity, respiratory function, children, physical activity, lifestyle Introduction Several studies have focused on elucidating the impact of homeostatic alterations on athletic performance across the diurnal cycle. These investigations have consistently demonstrated that athletes exhibit considerable discrepancies in their performance, contingent on the temporal occurrence of their exercise regimen. In these processes, known as circadian rhythm, previous studies have reported a positive effect of evening training on sporting performance compared with training in the morning.

It has been demonstrated that long-term combined strength and endurance training in the evening can result in greater increases in muscle hypertrophy and mass than training conducted in the morning. These findings have been consistently observed in cardiovascular fitness tests, such as swimming and cycling, and in strength tests, such as standing vertical jumps (countermovement jumps) and isometric muscle contractions. This variation in athletic performance is strongly associated with the mechanisms of circadian rhythm. Consequently, the circadian rhythm represents a crucial consideration in the development of training regimens.

The study of circadian rhythms, defined as the cyclic 24-hour patterns of physiological functions, including lung function, has emerged as a prominent area of interest in both basic and clinical research. The maintenance of circadian rhythms is regulated by the 'circadian clock', which is located in the suprachiasmatic nucleus of the hypothalamus. This process is organized by the hypothalamic-pituitary axis, the autonomic nervous system and clock proteins that form regulatory feedback loops. The suprachiasmatic nucleus in the hypothalamus serves as the primary circadian clock, generating these rhythms. It is synchronized with external cues, including light-dark cycles, mealtimes and social interactions. Furthermore, it regulates rhythmic changes in human physiology and coordinates the timing of processes such as the sleep-wake cycle, fluctuating activity levels and the synchronization of skeletal muscle functionality. Numerous factors related to circadian rhythm (body temperature, chronotype (morning type vs. evening type), training programs and daily fluctuations in biochemical markers) have been shown to contribute to diurnal variation in athletic performance. The presence of a circadian rhythm in lung function, which is one of these factors, is also known.

The capacity of the lungs to regulate oxygen intake during running is a key factor in both running economy and performance. It has been demonstrated in the literature that regular running training has a significant effect on performance peaks, with the greatest benefits observed when training is conducted in the morning. Additionally, when training is performed in the afternoon or evening, it has been shown to increase the amplitude of daily variations at the neuromuscular level. In the context of professional marathon running, evidence suggests that prioritizing morning training sessions may lead to enhanced performance outcomes. In the literature, running training, in which circadian rhythm is taken into account, is generally performed on adult and young athletes, but there are no studies on how morning running and evening running affect lower extremity strength and respiratory functions in studies on child athletes. Therefore, this study aimed to determine the effects of 8 weeks of morning running and evening running on lower extremity strength and respiratory function in 10-12-year-old male football players. It is hypothesized that the data obtained from morning and evening running training differ. This information may prove useful to coaches and sports scientists engaged in the design of training programmes in their professional capacities.