Adequate knowledge of trunk muscles is useful to provide the best possible treatment of low back pain, as well as for improvement of athletic performance. Thus, trunk muscle exercises are commonly performed and taught on the athletic field.

Muscle function in the neutral zone is important for trunk stabilization. Trunk muscles are classified into a local and a global muscle system. The local muscle system includes deeper muscles with their points of origin or insertion directly or indirectly on the lumbar vertebrae such as the transversus abdominis and the lumbar multifidus. The global muscle system includes muscles that are not directly attached to the lumbar vertebrae, such as the rectus abdominis and the external oblique muscles. Local muscles play a key role in trunk stability and postural responses. Hodges and Richardson reported that the onset of the transversus abdominis is earlier than that of agonist muscles (early activity) during upper limb movement. Moreover, local muscles are partially activated through low-load tasks and postural control such as with walking (tonic activity). In contrast, high-load movements such as running and jumping lead to co-activation of local and global muscles (phasic activity). Adequate training to achieve motor control of the local muscles using specific exercises is important to enhance optimal activation of trunk muscles during various movements. Therefore, I explain progressive trunk muscle training with electromyographic data from motor control exercise to bridge exercises and co-contraction of the trunk muscles along myofascial line.

Many studies investigated the effects of core stability training on athletic performance. Some recent systematic reviews revealed that core stability training provides marginal benefits to athletic performance. However, further research is necessary to better understand how trunk stability and stability affect athletic performance.

There is no clinical evaluation of lumbar and trunk functions that can reveal all the trunk functions in one evaluation. Therefor you have to understand the clinical evaluations assessment of lumbar and trunk functions of athletes. This paper introduced clinical evaluations of lumbar and trunk functions. The contents are movement evaluation (active movement, thoracic alignment evaluation during extension), spinal segmental mobility, trunk function evaluation (Manual Muscle Test), trunk endurance, Sharmann core stability test, and motor control. When used clinically, it is important to understand the pathology of low back pain of the athlete and evaluate the dysfunction. In addition, if medical rehabilitation is insufficient, the next stage of athletic training often does not proceed as expected. So it is recommended to improve the function of the trunk at the stage of medical rehabilitation.

Low back pain is one of the most common disorders for athletes. In the field of athletic training, various theories and methods of core stabilization exercises have been produced and verified whether it is effective for prevention of low back disorders and performance improvement. In this article, author reviewed clinical and scientific evidence about prevention of low back disorders for athletes. In the fact, there are few reports of well-designed research about the pain prevention of low back in the study of athletes. Although the evidence is low, some reports showed that re-education of deep trunk muscles (such as transversus abdominis and multifidus, etc.) and motor control training are effective in preventing the worsening or recurrence of low back pain in athletes. In the future, high-quality research is needed to verify both performance improvement and low back disorders prevention.

The diaphragm has been long-known as main gas exchange muscle for survival. However it has been revealed that breathing has many functions other than gas exchange, such as spinal decompression, postural stability, fluid dynamics, visceral health, and emotional regulation. For increasing attention to the core stability along with respiration, this article will review the fundamental structure and core stability function of the diaphragm as well as the recent research for low back pain. Then based on the diaphragmatic contribution to the core stability and low back pain, this article will discuss possibility of breathing exercises to normalize diaphragmatic position and function.

This study aimed to investigate how moods and emotions in university female athletes influence the occurrence of sports injury and disability. We further investigated how moods and emotions are influenced by environmental changes, such as the shift in coaches and year of study. Twenty-four female university volleyball players filled in the Japanese-version Short-form Profile of Mood States for four times between the end of February and the end of March 2018 in which they experienced shifts in coaches, and for five times between the beginning of April and the end of June 2018 in which they moved on to their next year of study. We analyzed 186 answers. The results suggested that the occurrence of sports injury was related to increased tension-anxiety, depression-dejection, and confusion. Moreover, tension-anxiety and confusion may increase with the change in coaches and year of study. As trainers are required to provide psychological support for athletes, they need to establish a relationship with athletes where the latter can easily express their moods and emotions.

Agility is one of the most important factors in sports performance. In addition to physical qualities such as leg muscle strength, perceptual and decision-making factors such as anticipation are also reported as important components of agility. Those cognitive functions are considered to be based on sport-specific experience. The purpose of this study was to investigate the cognitive functions among soccer players between different performance levels and ages while reacting in soccer-specific situations by using the video-based reactive test. Collegiate (high performance group, 26 players : age 20.0±0.8 years ; low performance group, 20 players : age 19.1±0.6 years) and junior high school (Jr. youth group, 19 players : age 13.2±0.8 years) male soccer players were recruited as participants. The athletes were instructed to react to a pass that was executed by a model in the video. The duration between presentation of stimulus (when the model in the video executed the pass) and initiation of subjective movement (when the subject started to move) was measured and compared between groups in addition to the complexity (single direction, multiple directions) or type of kick (inside kick, outside kick). A questionnaire about the reaction cue was also completed. The results showed that the time between the presentation of stimulus and initiation of subjective movement was significantly delayed in the more complex situation in each group. In addition, there was no difference in the time for inside kicks in the Jr. youth group compared to the high performance group, but the difference became significant in reactions to outside kicks. These results indicate that the experiences in cognitive functions while reacting in sport-specific situations are situation-based.

Anthropometry has been frequently utilized in a conditioning of athletes. Among anthropometric variables, skinfold thickness has been used as an indicator for total fat accumulation as well as distribution pattern of subcutaneous adipose tissues. In the present report, usefulness of skinfold thickness to monitor and provide appropriate conditioning of athletes was investigated. Twenty-one university rugby players (11 forwards and 10 backs) underwent body composition assessment using underwater weighing (UWW) method and also anthropometry using skinfold thickness measurements during the pre-season. Forward players showed greater triceps and subscapular skinfolds and backs players showed a greater subscapular skinfold compared with results reported in overseas. With assumption that less active muscle tissues resulted in a greater subcutaneous adipose tissue deposition, an exercise protocol of the upper back, particularly around subscapular region was modified. Modification in exercise protocol resulted in significant (p<0.05) reduction in subscapular skinfold. The results also showed tendency of reduction in triceps and increase in biceps skinfolds. The observed results of the present report may indicate that measurements of skinfold thickness may be useful to evaluate appropriateness of conditioning.