Effects of reformer pilates on body composition, strength, and psychosomatic factors in overweight and obese women A randomized controlled trial

Abstract

This study aims to examine the effects of Reformer Pilates exercises on body composition, strength, endurance, and psychosomatic parameters in overweight and obese women. The study is a randomized controlled study. A total of 47 overweight and obese women between the ages of 30–60, with a BMI of 25 kg/m² and above in the study. Two different groups were formed the exercise group (n:23, age: 46,70 ± 9,77 years) and the control group (n:24, age: 45,37 ± 9,63 years). Reformer Pilates exercises are given 3 times a week for 8 weeks. The upper extremity strength with a handgrip dynamometer, muscle endurance with McGill endurance test, body composition with Bioelectrical Impedance, sleep quality with Pittsburgh Sleep Quality Index, and depression/ anxiety level with The Hospital Anxiety and Depression Scale were evaluated. All evaluations were assessed before and after Reformer Pilates exercise training. There was a significant difference in body composition, upper extremity strength, endurance, and depression/anxiety scale (p values respectively 0.011; 0.000; 0.000; 0.025; 0.031) in the Reformer Pilates group. There were no statistical differences between the groups in the Pittsburgh Sleep Quality Index value (p = 0.055). Reformer Pilates improves body composition, increases muscle strength and endurance, and reduces depression and anxiety in overweight and obese women.

Trial registration: NCT05176912 (04/01/2022).

Obesity is a complex chronic disease in which abnormal or excess body fat (adiposity) impairs health, increases the risk of long-term medical complications, and reduces lifespan¹. American Association of Clinical Endocrinologists (AACE) and American College of Endocrinology (ACE) guidelines recommend using Body Mass Index calculation to evaluate overweight and obese individuals².

Obesity, essentially a result of the imbalance between energy intake and expenditure, has a complex etiology caused by many factors such as genetic³metabolic⁴ psychological⁵and lack of physical activity⁶. In recent years, the prevalence of obesity in adults ages 40–59 was 46.4%, which was higher than the prevalence in adults ages 20–39 (35.5%) and 60 and older (38.9%). In men, the rate is 39.2%, while in women, it is 41.3%.⁷ Obesity is associated with numerous health, social, and psychological issues, and individuals with obesity have an increased risk of diabetes, hyperlipidemia, hypertensive diseases, coronary heart disease, stroke, infarction, osteoarthritis, and endometrial, breast, and colon cancer⁷. Being overweight can cause breathing problems like sleep apnea, which can make sleep worse. Additionally, issues like joint pain and night sweats may cause sleep disruptions. Moreover, excess body weight can limit physical activity, leading to a decline in muscle strength. As a result, poor sleep quality and weak handgrip strength can both be results of obesity and factors that increase the risk of developing obesity⁸. Approximately 3.4 million adults die due to health issues caused by obesity and overweight. Of these individuals, 44% have diabetes, 23% have ischemic heart disease, and 7–41% have certain malignancies. A study has found that women with normal weight have better health, fewer chronic diseases, fewer complaints of sacrospinal pain and migraines, require less medical assistance, and have a higher quality of life⁷.

Obesity treatment includes behavioral changes such as lifestyle changes and increasing physical activity, as well as individual-specific strategies that may include psychological, pharmacological, and surgical methods⁹. Increased physical activity and reduced food intake are effective approaches in the long-term management of obesity¹⁰.

Data indicate that physical activity can improve other markers of health in normal-weight and overweight individuals, such as overall quality of life, brain health, cognition, memory, sleep, and anxiety^11,12 Furthermore, the studies on overweight and obese individuals show that regular physical activity reduces many physical and physiological health problems that develop due to obesity and reduces mortality by reducing subcutaneous and visceral fat^13,14. Moreover, physical activity has positive effects on psychological aspects and self-confidence in obese individuals¹³.

The most effective exercise method in the treatment of overweight and obese individuals is long-term (30 min or more) and moderate-intensity exercises¹³. In addition to this, Pilates is also preferred as an alternative exercise method¹⁴. Mat Pilates exercises positively affect Body Mass Index (BMI) fat percentage, waist/hip fat ratio, and muscle strength in overweight and obese individuals¹⁵. Many studies have shown that regular jogging improves metabolic risk factors (diabetes, hypertension)¹⁶aerobic dance-based exercise training increases muscle strength and endurance¹⁷and High-Intensity Interval Training (HIIT) training significantly reduces body weight and body fat percentage¹⁸. Although Reformer Pilates is a less severe exercise than aerobic, dance, and HIIT exercises, it is an important exercise for a healthy body with concentration, control, centering, movement rhythm sensitivity, and breathing techniques during practice. Studies have been reported to have positive effects on lean mass and body values¹⁹.

In addition to Pilates, Pilates with equipment designed by Joseph Pilates after the First World War for the rehabilitation of wounded soldiers, is now used in the treatment of obesity¹⁶. Reformer Pilates, a resistance exercise device, consists of a sliding platform within a wooden or metal frame connected to a system of springs, pulleys, and ropes¹⁷. Reformer is an ideal device for use especially in overweight and obese individuals because it provides a low-load form of exercise that helps the joints and its cost is more economical compared to other non-invasive methods¹⁸. In the twentieth century, it became widely known among women in particular. Women generally prefer Reformer Pilates (RP) exercises for aesthetic purposes such as losing weight, slimming, staying in shape, strengthening muscles, getting rid of muscle pain, and gaining flexibility^16,19,20,19. A few studies show that RP exercises, with their focus on precision and control, strengthen the communication between the nervous system and muscles, improve overall neuromuscular control, and positively affect body composition (body weight, BMI, fat percentage) and muscle strength in overweight individuals²⁰. In the literature, the number of studies investigating the effects of RP exercises on overweight and/or obese individuals is limited, and these studies focus on the anthropometric characteristics of individuals.

To our knowledge, a few studies have explored the effects of RP exercises in obese and overweight women, and these studies focus on the anthropometric characteristics of individuals. Therefore, this study aims to assess the effects of Reformer Pilates on body composition, muscle strength, endurance, sleep quality, and psychosomatic parameters in overweight and obese women.

Methods

Study design

This study was designed as a randomized controlled trial study. The participants were randomly assigned to 2 groups, i.e., the exercise group (EG) and control group (CG). All evaluations and exercises in the study were performed at the Eastern Mediterranean University Sports Health Unit.

Participants

A total of 47 overweight and obese women who met the inclusion criteria were evaluated.

The inclusion criteria for this study were as follows: age between 30 and 60, with a sedentary lifestyle, individuals who do not control their diet, physical activity levels, and a BMI of 25 kg/m² and above. The physical activity levels of the individuals included in the study were determined using the International Physical Activity Questionnaire. Only female individuals were included in the study because obesity and overweight are more common in women than in men²¹. Patients were excluded from the study if they had any of the following criteria: Diagnosis of neurological, cardiovascular, or psychological problems, those who had a musculoskeletal system injury in the last year, regular medication users and individuals who participated in any regular physical activity program in the last 6 months were excluded from the study. Written and verbal consent was obtained from patients who met the inclusion criteria and the procedure was explained by the researcher. Before the study, informed consent was obtained from all subjects. This study was approved by the Eastern Mediterranean University Ethics Committee in April 2021 (numbered 2021/02). Clinical trial registration number: NCT05176912 (04/01/2022). This study was conducted by the Declaration of Helsinki guidelines.

Sample size calculation

In the study conducted by Rayes et al. in 2019, titled “The effects of Pilates vs. aerobic training on cardiorespiratory fitness, isokinetic muscle strength, body composition, and functional tasks outcomes for individuals who are overweight/obese: a clinical trial, “²² the primary outcome was the change in body fat percentage, and the effect size was determined to be f = 0.825. Accordingly, assuming that the effect size in our study would be high, the required sample size was calculated as 47 participants based on a 95% power (1-β = 0.95), an effect size of f = 0.80, and a significance level of α = 0.05, using the G*Power 3.1.9.2 software²³.

Randomization and blinding

Patients who met the inclusion criteria were randomly allocated to the EG or CG using GraphPad software and a simple randomization technique. As a result of randomization, 23 participants were included in the EG and 24 participants were included in the CG (Fig. 1). All the volunteers were blinded and did not know the groups to which they belonged. The risk of selection bias was minimized due to the simple randomization technique used for randomization. However, the outcome assessors were not blinded.

Fig. 1.

Flow diagram showing the flow of participants through each stage of trial.

Intervention

Exercise group

The EG was given the RP exercise program under the supervision of a physiotherapist for 50–60 min, 3 days a week for 8 weeks. Before the first training session, a practice session was held to familiarize the volunteers with the Reformer machine, the exercises to be performed, and the six principles of the Pilates method. The exercise program was carried out in three stages: warm-up (10 min), exercise training (40 min), and cool-down (10 min) periods. The intensity of the program was progressively increased by applying beginner level for 1–2 weeks (Single leg stretch, double leg stretch, swimming, obliques (Fig. 2), spine twist, spine stretch forward), intermediate level for 3–6 weeks (Roll-up, hundred (Fig. 3), side bend, side leg series, scooter (Fig. 4), footwork toes, single leg series, double leg series), and advance level for 7–8 weeks (Hundred, side kick (front/back), rowing, swan, teaser (Fig. 5), side bend, side kick (small circles)) to participants. At the beginner level, exercises were performed with 2 sets of 10 repetitions using green and yellow springs. Intermediate-level exercises were performed using green and blue springs for 2 sets of 12 repetitions, and advanced-level exercises were performed using green and blue springs for 2 sets of 15 repetitions. All exercise sessions were performed with musical accompaniment.

Fig. 2.

Obliques.

Fig. 3.

Hundred (Start and end).

Fig. 4.

Scooter.

Fig. 5.

Teaser.

Control group

Participants in the CG were also informed about the study, and their consent was obtained. The control group, unlike the experimental group, agreed not to receive any treatment or intervention. Generally, taking into account that the control group does not receive any treatment, the health status and changes in the individuals of the group were monitored. The CG consisted of participants who received no intervention, did not engage in exercise, and did not make any changes to their dietary habits throughout the study period. Individuals in this group continued their natural lifestyle.

Outcome measures

All results were measured by the same physiotherapist before treatment and at the end of the 8th week of the intervention.

Sociodemographic evaluation

Age, gender, sports habits, alcohol, cigarette, and drug consumption of the individuals were questioned. Moreover, body composition (body weight, BMI, and body fat percentage) was measured with a bioelectrical impedance device (InBody 270). The heights of the individuals were measured with a tape measure and recorded in meters. During the day, body weight may vary depending on water balance, so each measurement was taken at the same time and on an empty stomach. Participants were instructed to refrain from eating at least 4 h before the measurement and to discontinue fluid intake at least 2 h before the assessment. In addition, measurements were taken before exercise, as measurements taken immediately after exercise may be misleading due to factors such as muscle swelling and water retention. Participants wore light clothing and removed metal items like buckles, jewelry, and belts during the measurements.

Upper extremity muscle strength

Handgrip strength is considered an indicator of overall muscle health and physical strength. A handgrip dynamometer was used to evaluate upper extremity muscle strength. To do the test, the participants were asked to sit upright in a chair with back support. The person was prepared with the knee and hip at 90⁰ flexion, the forearm in neutral position, and the wrist in 0–30⁰ extension. During the measurement, the person was asked to squeeze the handles of the dynamometer as strongly as possible. 3 measurements were made at 1-minute intervals. As test results, the average values ​​of the measurements were taken and recorded in ‘kg’²⁴.

Muscle endurance

The McGill Muscular Endurance Test is a set of four isometric endurance tests designed to assess the ability of the trunk muscles to stabilize the spine under static, loaded conditions. These tests include trunk flexion, extension, and left and right lateral flexion endurance. The tests are timed, and the duration the participant can maintain the prescribed position is recorded²⁵.

Sleep quality assessment

The Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep quality. The PSQI includes a total of 24 questions, 19 of which are self-assessment questions and 5 of which are answered by the individual’s spouse or a roommate. These items create 7 component scores: sleep quality, sleep latency, sleep duration, habitual sleep activity, sleep disturbance, sleep medication use, and daytime dysfunction. Higher scores indicate worse subjective sleep quality²⁶.

Anxiety and depression assessment

The Hospital Anxiety and Depression Scale (HADS) was used to assess anxiety and depression. This self-administered rating questionnaire consists of 14 items, 7 related to anxiety and 7 to depression. The items in the scale are evaluated on a 4-point Likert scale and are based on a scoring system between 0 and 3. It is stated that for each subscale, 0–7 points are the normal range, 8–10 points suggest the presence of a mood disorder, and 11 and above points indicate a possible mood disorder. Additionally, there are recommended points as mild (8–10 points), moderate (11–15), and severe (16 and above) cases²⁷.

Statistical analysis

Data were analyzed using the Statistical Package for Social Sciences (SPSS) 27.0 software. Before statistical tests were used, the normal distribution assumptions of the data were checked with the Shapiro–Wilk test, and it was determined that they conformed to normal distribution. The distribution of the participants according to their socio-demographic characteristics was examined with frequency analysis and shown in cross tables. The mean (x) ± standard deviation (SD) as appropriate, was calculated for each variable. Statistical significance was set at p-value < 0.05. In this context, the Analysis of Covariance (ANCOVA)²⁸ was applied to compare the changes in pre-test and post-test body composition, muscle strength, endurance, and psychosomatic measurements of the exercise and control group participants. In the ANCOVA analysis, the effect size was assessed using eta squared (η²). According to Cohen’s classification, an η² value below 0.01 is considered negligible, between 0.01 and 0.06 indicates a small effect, between 0.06 and 0.14 indicates a medium effect and values equal to or above 0.14 indicate a large effect.

Results

The EG and the CG were similar in terms of their mean age, gender, educational level, sports habits, cigarette, alcohol, and drug use of the participants according to their groups (Table 1).

Table 1.

Socio-demographic characteristics of the participants.

	Exercise (n = 23)		Control(n = 24)		Total (n = 47)
	n	%	n	%	n	%	p
Age	46,70 ± 9,77		45,37 ± 9,63		46,02 ± 9,62		0,643
Educational status
Primary education	1	4,35	7	29,17	8	17,02
High School	8	34,78	9	37,50	17	36,17	-
Undergraduate and above	14	60,87	8	33,33	22	46,81
Smoking
Yes	4	17,39	4	16,67	8	17,02	0,625
None	19	82,61	20	83,33	39	82,98
Alcohol use
None	23	100,0	24	100,0	47	100,0	-
Drug use
None	23	100,0	24	100,0	47	100,0	-

The assumptions of the chi-square test were not met.

In a comparison of the groups in terms of their body composition, muscle mass, BMI, and fat percentage measurements of the individuals included in the study, statistically significant differences were observed between the changes in body weight, muscle mass, BMI, and fat percentage values (p < 0.05, p values: p = 0.011, 0.019, 0.00, 0.00, respectively). The decrease in measured body weight, BMI, and fat percentage values and the increase in muscle mass of the individuals in the EG were found to be higher than those of the CG participants (Table 2).

Table 2.

Comparison of participants’ body composition measurements.

	Group	Pre Test		Post Test		F	p	η2
		x̅	SD	x̅	SD
Body weight (kg)	Exercise	76,04	7,01	74,67	6,67	7,005	0,011*	0,137
	Control	75,03	7,28	75,32	7,24
Muscle weight (kg)	Exercise	24,92	2,23	25,61	2,37	5,981	0,019*	0,120
	Control	23,03	4,88	23,68	1,95
Body Mass Index (kg/m²)	Exercise	29,09	2,61	28,53	2,48	16,569	0,000**	0,274
	Control	29,00	2,60	29,24	2,71
Fat mass (%)	Exercise	39,26	4,92	37,29	5,04	41,249	0,000**	0,484
	Control	39,51	4,96	40,17	5,11

*p < 0.05, **p < 0,01, x̅ = arithmetic mean, SD = standard deviation, F = ANCOVA test statistical value, η² = Eta² (effect size).

Table 3 shows the values ​​regarding the physical abilities of the individuals included in the study. The difference between the observed changes in the muscle strength and muscle endurance values ​​of the individuals in the EG and CG participating in the study at the pre-test and post-test was statistically significant (p = 0.00 for all tests). The increase in the right and left upper extremity grip strength, trunk muscle endurance, back endurance, and right and left lateral bridge test values of the participants in the exercise group were higher than those of the participants in the control group (Table 3).

Table 3.

Comparison of participants’ muscle strength and muscle endurance.

	Group	Pre Test		Post Test		F	p	η2
		x̅	SD	x̅	SD
Right upper extremity strength	Exercise	20,88	4,38	23,36	3,87	45,568	0,000**	0,509
	Control	20,75	4,55	19,66	4,98
Left upper extremity strength	Exercise	20,06	3,65	21,99	3,81	16,304	0,000**	0,270
	Control	19,77	3,68	19,37	2,90
	Control	8,68	1,77	7,75	1,78
Trunk flexör endurance test	Exercise	15,29	7,88	27,36	12,02	85,728	0,000**	0,661
	Control	11,38	4,13	9,41	3,76
Back endurance test	Exercise	11,53	6,20	18,57	6,88	82,959	0,000**	0,653
	Control	7,92	1,90	7,20	2,06
Right lateral bridge test	Exercise	11,19	6,78	18,96	7,67	56,704	0,000**	0,563
	Control	10,00	4,50	9,43	6,06
Left lateral bridge test	Exercise	10,77	5,51	18,50	7,06	108,251	0,000**	0,711
	Control	9,71	4,89	9,22	5,39
	Control	31,50	2,69	31,21	2,69

*p < 0.05, **p < 0.01, x̅ = arithmetic mean, SD = standard deviation, F = ANCOVA test statistical value, η² = Eta² (effect size).

As demonstrated in Table 4, no statistically significant difference was found between the amounts of change observed in the pre-test and post-test PSQI scores of individuals in the EG and CG (p > 0.05). However, statistically significant differences were observed between the amounts of change observed in the HADS scores of individuals in the EG and CG included in the study (p > 0.05, p values ​​p = 0.025, 0.031, respectively) (Table 4).

Table 4.

Comparison of participants’ PSQI and HADS measurements.

	Group	Pre Test		Post Test		F	p	η2
		x̅	SD	x̅	SD
Pittsburgh Sleep Quality	Exercise	10,96	4,41	10,43	4,04	3,877	0,055	0,081
	Control	13,71	3,14	13,92	3,30
Depression	Exercise	4,04	2,93	3,26	2,73	5,434	0,025*	0,112
	Control	4,92	4,36	5,35	4,85
Anxiety	Exercise	5,30	3,23	3,96	3,46	4,994	0,031*	0,104
	Control	7,43	4,82	7,09	4,90

*p < 0,05, **p < 0,01, x̅ = arithmetic mean, SD = standard deviation, F = ANCOVA test statistical value, η² = Eta² (effect size).

Discussion

This randomized controlled trial investigated the effects of an 8-week RP program on body composition, upper extremity strength, endurance, sleep quality, and psychological well-being in overweight and obese women. The findings from this randomized controlled trial indicate significant improvements in body composition, muscular strength, endurance, and psychosomatic parameters following the intervention, with no observable change in sleep quality.

The literature consistently supports the role of regular exercise in improving body composition and metabolic outcomes²⁹. In a study conducted on healthy individuals, it was found that RP exercises applied 2 days a week for 9 weeks reduced the fat rate, increased the muscle ratio, and caused significant improvements in BMI data³⁰. Studies in the literature show that RP exercises performed twice a week by healthy individuals increase muscle mass, reduce fat percentage, and improve BMI values^20,31. Specifically, RP exercises performed 2–3 times per week have been shown to reduce fat percentage, increase muscle mass, and improve BMI in obese women^32,33. These results suggest that the RP group showed significant improvements in these parameters, which may likely be due to the use of spring-based resistance and a structured increase in exercise intensity during the program.

Upper extremity strength, measured with handgrip testing, also improved significantly in the RP group. This is consistent with research showing that RP can increase grip strength in postmenopausal women²⁴improve trunk and lower body strength in middle-aged adults³⁴and increase grip strength³⁵back and leg strength³⁶and upper extremity strength³⁷ in sedentary women. The authors report that using resistance tools like springs or therabands helps muscles get stronger and can lead to muscle growth^37,38. Although muscle strength usually starts to decrease in the late 20s³⁹studies show that RP can help improve strength in both middle-aged and older adults^34,37,36. The observed gains in handgrip strength may be attributed to the progressive increase in resistance and repetitions introduced after the third week of training, in combination with the use of spring-based resistance equipment.

RP exercises target core musculature, including the transversus abdominis, multifidus, diaphragm, and pelvic floor, thereby improving trunk stabilization and functional endurance³⁹. Previous research showed that RP training, when performed twice weekly in healthy individuals, improves endurance of the trunk flexor muscles⁴⁰ and enhances both upper and lower extremity muscular endurance³⁷. Muscular endurance, particularly in the trunk and upper extremities, also improved significantly in the RP group. Additionally, the incorporation of breathing techniques may have enhanced oxygen delivery to skeletal muscles, contributing to increased muscular endurance. These findings align with existing literature supporting RP’s efficacy in improving core strength and endurance.

Although sleep quality is a multifaceted issue influenced by various physiological and psychological factors, our study found no significant changes in sleep quality following RP training. While previous meta-analyses have demonstrated some benefit of mat Pilates for sleep parameters, these effects appear limited in populations with complex sleep disturbances, such as vasomotor symptoms in postmenopausal women⁴¹individuals with chronic conditions⁴²and by stress and infant behavior in postpartum women⁴³. Hormonal changes among female participants may have played a role in mitigating potential improvements in this domain.

Physical activity is a key approach to improve quality of life and emotional well-being, while also reducing obesity-related issues like depression and anxiety⁴⁴. It is known that Pilates exercises are effective on depression and anxiety by increasing the release of serotonin⁴⁵. The RP program led to a moderate improvement in depression and anxiety levels. These results match earlier studies that show Pilates can help with mental health. This may be because Pilates improves how people see their bodies, changes brain chemicals like serotonin, and includes calming, meditative movements. Also, using music and focusing on breathing may have helped improve mood, motivation, and sticking to the program, making the benefits even stronger.

In summary, this study observed large effect sizes in BMI, upper extremity muscle strength, trunk flexor, back, and lateral bridge values following RP exercise training, while middle effect sizes were found in depression and anxiety values. These results suggest that RP has strong and clinically significant effects, particularly on BMI, upper extremity strength, and endurance. Accordingly, this strongly supports the effectiveness of RP as an intervention for improving health in overweight and obese women.

Conclusions

The results of our study showed that Reformer Pilates exercises are an effective exercise method that can be used to improve body composition, muscular strength, muscular endurance, and psychosomatic factors in overweight and obese women. According to the results, it can be concluded that the implementation of Reformer Pilates exercise programs has a positive effect on health parameters.

Limitations

This study has certain limitations. One is the lack of investigation of blood parameters in overweight and obese women, and another is the absence of blinding of outcome assessors. Measuring blood parameters could have added biological depth to the findings and enabled a more comprehensive understanding of the effects of exercise on the body. Additional limitations include the small sample size, lack of dietary control, short intervention period, and lack of long-term follow-up, future studies are recommended to include longer interventions and extended follow-up periods. Moreover, the findings of this study apply only to overweight and obese women and cannot be generalized to male individuals or women outside of this classification.

Author contributions

Conceptualization: O.G. and B.K.; methodology: O.G. and B.K.; writing—original draft preparation: O.G.; writing—review and editing: O.G. and B.K.; supervision: B.K. All authors reviewed the manuscript.

Data availability

The datasets collected during and/or analyzed during the current study are available from the corresponding author upon reasonable request.

Declarations

Competing interests

The authors declare no competing interests.