Changes in Physical Fitness Factors and Some Anthropometric Indices of Inactive Young Women Following Eight Weeks of Cross-Fit Training

Sedentary lifestyle causes overweight in women, obesity in women is associated with the development of physical problems and metabolic diseases, such as diabetes, hypertension, cardiovascular disease, some cancers, anxiety and personality disorders and Osteoarthritis is one of the effects of inactivity in women (2).Cross-fit training, which is a combination of resistance and explosive training, has shown a greater increase in speed and physical strength compared to traditional training methods (6). High-intensity exercise training and short rest periods in cross-fit exercise have resulted in fitness and improve muscle strength, muscle endurance, aerobic fitness, and body composition (7). These exercises affect the four components of health-related physical fitness (aerobic fitness, physical fitness, body composition and flexibility) athletes (8). Some studies have examined the effect of cross-fit exercises on some physical and anthropometric parameters, but have stated conflicting results. Women athletes who have combined cross-fit training with their training have experienced many improvements in professional sports (9). Smith et al (2013) reported that cross-fit improved aerobic and muscular endurance, and that fitness factors altered the vo2max of young women after a 10-week period of cross-fit training compared to traditional exercise (11). However, in Patel et al (2008) study on overweight and obese adults, no significant changes in body composition were observed after 8 weeks of cross-fit training (12). Also, in Blocker et al (2015) study, conventional training methods were compared with new training methods, including cross-fit training in healthy men after 6 weeks. In this study, it was concluded that although significant difference in strength improvement was observed, but there was no significant difference in terms of improving cardiovascular endurance (24). Knowing effective training methods can play an important role in preventing disease progression and reducing treatment costs in sedentary people. Therefore, the study of safe and effective methods to maintain and develop physical fitness for a wide range of people has always been the focus of researchers. Cross-fit exercises are useful for everyone and compared to other traditional training programs, this type of exercise requires less time (14). As mentioned, studies on the effect of cross-fit exercises on physical and anthropometric parameters in some cases have different results and the reports are ambiguous. Therefore, the aim of this study was to investigate the changes in physical fitness factors and some anthropometric indices of inactive young women following eight weeks of cross-fit training.

In this semi-experimental study, 20 inactive young women (age 24.9±2.40 years, Body mass index 22.2.2±7.7 kg/m2) from the Shiraz city were purposefully and accessibly selected and randomly assigned to exercise and control groups. The experimental group performed cross-fit exercise program 3 sessions per week, each session 60 minutes with intensity of 50 to 60% of the maximum repetition for 8 weeks. Changes in physical fitness factors and anthropometric indices of subjects were measured using Rockport test, sit-ups, 4×9 meters agility shuttle run, 45-m sprint and Sargent jump test. Data were analyzed by independent and dependent t-test at the p<0.05.

The results showed that cardiorespiratory endurance (40.4 vs. 33.9), trunk muscle strength (34.1 vs. 24.5), speed (6.81 vs. 8.07), lower muscle power (36.6 vs. 29.8) and agility (13.4 vs. 16.6) increased significantly in the exercise group compared to the control group. Also, after 8 weeks, body mass index, waist circumference and pelvic circumference in the experimental group decreased significantly compared to the control group (p=0.001).

The findings of the present study show that eight weeks of cross-fit training improved cardiorespiratory endurance, torso muscle strength, speed, lower torso muscle strength and body agility. The findings of this study were consistent with the results of Previous research (11, 15-18). Although the physiological mechanisms of changes in post-fit fitness have not yet been identified, it is possible that exercise specificity may play a role in the metabolic adaptations observed in these changes (22, 23). Improving cardiorespiratory endurance can be specific to the type of activity. In the present study, cardiorespiratory endurance is similar to the improvement in VO2max observed following resistance training or moderate to high intensity running (24). In fact, the variety of cross-fit exercise programs can explain these results. The increase in torso muscle strength after cross-fit training in the present study is similar to the Goins study, which showed 12%, 13% and 8% improvement in weight lifted during Deadlift 1-RM, squats and shoulder presses after six weeks of cross-fit training, respectively. Reported in recreational exercise (15). In the present study, weights of about 50 to 60% of the maximum repetition of individuals were used and an improvement in trunk muscle strength was observed compared to the control group, while some studies have shown that cross-fit training can be compared to resistance training, according to ACSM guidelines can further increase muscle strength measured by the Margaria-Kalamen test (28). Some studies have also reported that people who exercised according to ACSM guidelines developed greater improvements in cross-fit guidelines. Experience muscle strength (measured by standing length jumps) (29). The number and duration of cross-fit training sessions per week has the greatest effect on changing body composition. In one study, during two sessions of cross-fit training with participants, training showed that experience level was a determining factor in achieving progress (9). on the other hand, even when exercise was a useful tool for maintaining body mass. Diet plays a key role in improving these parameters. Finally, comparing the present results with the results of previous studies, the initial level of physical fitness factors can play an important role in post-program changes. In trained subjects, the capacity to improve these parameters may be less than the capacity of sedentary participants. Cross-fit exercises were one of the strengths of the present study; This is because this type of exercise can have different answers and adaptations than other exercise programs. However, understanding the effects of cross-fit training on fitness requires more research. There were some limitations in the present study, such as not measuring other indicators of physical fitness, measuring body composition (adipose tissue and lean body mass) and muscle damage following this type of exercise. It can help to better explain and interpret the results in sedentary women, and ultimately diet is a limiting factor in achieving changes in body composition, so controlling the diet during the exercise protocol can provide an understanding of the results obtained. This is a research weakness suggested by future studies to measure these factors in sedentary women. According to the results, Cross-fit training could possibly improve the fitness and anthropometric indices of inactive women.