Effects of 16-Week Circuit Training on Spine Structure, Trunk Muscle Endurance, and Balance in Healthy Women

Circuit training (CT) was developed by Morgan and Anderson in 1953, and is a type of training that includes various exercise stations arranged in a certain order. During CT, each participant performs 8 to 20 repetitions of exercise at each station, usually in less than a minute. Also, each participant moves from one training station to another with short rest periods or without breaks, and ends a training session by completing all stations. This training includes exercises performed with only body weight without the use of any equipment or with ancillary equipment such as elastic bands, free weights, and exercise devices, or a combination of both types of exercise.

It is seen that CT, which is a method frequently preferred by individuals of all ages all over the world to improve or maintain both physical performance, and health-related fitness, is gaining popularity due to its practicality and efficiency in recent years. Especially, it has become an important exercise option for individuals who have the problem of 'not having enough time for exercise' in daily life. The fact that the intensity can be adjusted according to the individual participant, that it includes both aerobic exercises and strengthening and endurance exercises for the trunk, upper and lower extremity muscles, and that it aims to improve both the musculoskeletal and cardiovascular systems of the participants is an important factor that increases the preferability of this training in all populations. Also, it is reported that the inclusion of various types of exercise in this exercise training greatly reduces the rate of participants dropping out of this type of training or ending it completely compared to other types of training. Lastly, the main feature of this exercise training, which allows individual interaction both among the participants and between the participants and the sports or health professionals who provides this training, is that it includes a combination of different types of exercises in order to improve both the musculoskeletal, and cardiovascular systems.

In the literature, it was seen that studies investigating the effects of CT on trunk muscle endurance included different populations. However, there were few studies investigating the effects of CT on endurance of trunk muscles in healthy women. Also, it was seen that there was not enough evidence in the current literature about the effects of CT on the spine structure in healthy women. Especially, a possible increase in endurance of trunk muscles after training may also positively affect spine structure via the kinetic chain. Lastly, it was concluded that studies investigating the effects of CT on balance mostly included patients with neurological disorders or the youth population. A possible positive effects on the spine structure via the kinetic chain may improve balance by increasing neuromuscular control in healthy women. This issue needs detailed investigation.

Therefore, the aim of this study was to investigate the effects of 16-week CT on spine structure, trunk muscle endurance, and balance in healthy women. Also, the investigators hypothesized that the 16-week CT would be positive effects on spine structure, trunk muscle endurance, and balance in healthy women.