Does better posture mean less body fat? Pilates studies give different answers for weight, fat, flexibility and core endurance. Learn how to read them.
When someone says Pilates changes your posture, it is easy to picture a smaller waist as well as a straighter back. Yet a score describing how you stand and a measurement of body fat percentage answer different questions. Before deciding what you want from an exercise that works your torso, it helps to separate expectations about posture from expectations about fat. A change that feels clear during a movement still needs the appropriate measurement if you want to describe it as a change in body composition.
In a controlled trial involving women with and without obesity, posture scores improved in both populations, while body composition results differed according to obesity status. In another trial involving older women, strength and physical performance improved, but the researchers did not establish an improvement in body composition. These findings make the choice of assessment important: a test of movement cannot simply stand in for a measurement of fat, and a measurement of fat cannot tell the whole story about movement.[14][18]
Pilates does not need to be a universal shortcut to weight loss to have a place in your routine. Equally, the scale does not need to decide the value of every exercise session. The useful question is what the research actually measured, in whom, and against which comparison. This feature separates core endurance, posture and body fat. For broader exercise comparisons, see our feature on aerobic exercise and resistance training; for yoga and weight, see our yoga research feature.
Working your core and reducing fat are different goals
Pilates research describes aims including core strength and endurance, core stability and joint flexibility through whole-body exercise. Here, the core means the torso, and endurance means the ability to keep muscles working. In an equipment-based trial, researchers assessed torso muscle endurance and forward-reaching flexibility with dedicated tests. They measured weight and body composition separately. That separation in the study design is useful when choosing your own goal: the researchers did not assume that completing a torso endurance test told them how much fat a participant had lost.[7]
Wanting to engage your abdomen more comfortably and wanting to reduce body fat can feel like closely related ambitions. They concern the same general area of the body, but they ask for different evidence. Movement and endurance assessments address the first ambition. Body fat measurements address the second. An improvement in muscular endurance, by itself, cannot establish a reduction in abdominal fat. The equipment trial gives information about several outcomes, but each outcome still has to be read through the test that produced it.[7]
The trial involving women with and without obesity illustrates why the distinction matters. Both populations improved their posture scores. Women without obesity, however, showed no effect on body mass index or body fat percentage. Researchers assessed posture with a score and body composition with those separate indicators before and after the exercise program. If you heard only that posture improved, you would miss the result for body fat. If you heard only that body fat did not change in women without obesity, you would miss the posture finding.[14]
Body composition itself is also a collection of measurements, rather than a single result. The studies discussed here examined weight, body fat percentage, lean mass and waist circumference. Lean mass refers to the body’s non-fat components; it should not automatically be read as muscle alone. The equipment-based trial also assessed water, and changes in its estimates of lean mass accompanied changes in water measurements.[1][7]
For someone looking in the mirror after a lesson, the practical implication is to name the question before naming the success. You might be interested in how you stand, how long you can maintain a movement, or whether a body fat measurement changes. These can remain separate goals within the same routine. The trials show why you should not require them to move together, or use improvement in one as evidence that another must have improved.[7][14]
初日の汗は、予約した人だけが持ち帰れる。
A favorable weight-loss analysis also found unchanged outcomes
A meta-analysis pooled 11 randomized controlled trials of Pilates in adults with overweight or obesity, bringing together results from a total of 393 participants. Random allocation helps limit the influence of pre-existing differences between people assigned to exercise and those assigned to a comparison condition.[1]
In this analysis, the mean difference between Pilates and comparison conditions was −2.40 kg for body weight and −4.22 percentage points for body fat percentage. The 95% confidence interval for weight was −4.04 to −0.77 kg; for body fat percentage, it was −6.44 to −2.01 percentage points. Percentage points are the appropriate description of a difference in body fat percentage. They do not describe the percentage reduction in the actual weight of a person’s fat.[1]
The intervals around the pooled weight and body fat estimates indicate uncertainty in the average differences from comparison conditions. The trials varied in participant body sizes, exercise programs and intervention lengths. Some comparisons involved other exercise, while others involved no intervention.[1]
The same analysis found no significant effect on waist circumference. The mean difference was −2.65 cm, with a confidence interval from −6.84 to 1.55 cm. Lean mass also showed no significant effect: the mean difference was approximately 0 kg, with a confidence interval from −1.40 to 1.40 kg. These findings sit alongside the favorable weight and body fat percentage results.[1]
No significant difference does not mean the research has proved that nothing can ever happen. It means the available data did not clearly establish a difference against the comparison condition for that outcome. For a reader whose main interest is their waist, the distinction is practical. The favorable average for body fat percentage cannot be converted into a promise about waist circumference when the analysis itself reported different conclusions for those measures.[1]
Results also varied across studies. The heterogeneity indicator, which describes variation between study results, was 88% for body fat percentage, 51% for weight and 61% for body mass index. The researchers reported more pronounced weight and body fat percentage reductions in studies including only participants with obesity. Longer interventions tended to show clearer changes in weight and body mass index. They nevertheless called for larger, well-designed randomized trials with better methods and reporting to confirm the results.[1]
Body mass index fell significantly too, with a mean difference of −1.17 and a 95% confidence interval from −1.85 to −0.50. Heterogeneity was 0% for waist circumference and 23% for lean mass, lower than for body fat percentage. These values show that uncertainty is not identical across all the outcomes in the same review. Looking at who took part and how long they exercised is useful, but so is looking at which measurement produced the most variable findings.[1]
Showing a change is different from outperforming another exercise
Another meta-analysis examined mat Pilates in healthy adults and included 10 studies. It did not find mat Pilates superior to traditional exercise or control conditions for body mass index, lean mass, body fat percentage or abdominal circumference. Body mass index (BMI) was the weight-relative-to-height indicator assessed in these mat Pilates comparisons. Exploratory analyses separating older people, adults and people with overweight or obesity also did not establish superiority for the outcomes examined.[3]
That conclusion may appear to conflict with the favorable analysis of adults with overweight or obesity. Before choosing which conclusion to believe, look at the question each review asked. One focused on adults with overweight or obesity; the other addressed mat Pilates in healthy adults. Exercise format and comparison conditions also matter. Comparing Pilates with another exercise is not the same research question as comparing it with no intervention. These differences need to remain visible when the conclusions are placed side by side.[1][3]
Imagine a measurement falls after an exercise program. If it also falls by a similar amount in the comparison group, the before-and-after change alone cannot show that Pilates produced a distinctive advantage. Whether a group changed and whether it changed more than another group are separate questions. The mat Pilates review primarily addressed the question of superiority against its comparison conditions. Its result should not be rewritten as evidence that every participant experienced no change, just as a before-and-after improvement should not automatically become evidence of superiority.[3]
A newer systematic review and meta-analysis of adult women also gave a mixed picture. It included 12 studies and approximately 540 participants. The mean difference in weight was −3.99 kg, with a 95% confidence interval from −6.30 to −1.67 kg. However, pooled effects were not significant for body fat percentage, waist circumference or lean mass. The weight result and the body fat percentage result therefore led to different conclusions within the same review.[2]
Forward-reaching flexibility did improve significantly in that analysis. The standardized mean difference was 0.69, with a 95% confidence interval from 0.43 to 0.94. A standardized mean difference expresses results on a comparable scale; this figure is not a weight change in kilograms. It describes flexibility. A reader hoping to move more comfortably may reasonably pay attention to that outcome, while a reader interested in fat loss needs to keep examining the body fat findings. The review can speak to both readers without giving them the same answer.[2]
The three reviews leave different conclusions on the table. The analysis of adults with overweight or obesity supported reductions in weight and body fat percentage.[1] The healthy-adult mat Pilates analysis did not establish superior body composition results against other exercise or control conditions.[3] The newer review of women urged cautious interpretation because study designs, exercise programs and methodological quality varied.[2]
BMI also fell significantly in the review of women: the mean difference was −1.22, with a 95% confidence interval from −1.83 to −0.61. Yet that decline in a weight-and-height indicator did not coincide with a significant pooled effect on body fat percentage. The review also considered strength, balance, physical performance and respiratory function. Pooled effects were not significant for handgrip strength, vertical jump or waist-to-hip ratio. Favorable flexibility findings did not extend uniformly to every test of physical ability or body composition.[2]
The review additionally described individual study findings in a narrative synthesis, separate from the numerical pooling. That part suggested further benefits for muscular strength, endurance, balance, functional abilities and respiratory measures. The pooled handgrip finding and the narrative account of strength therefore need to be distinguished. Which tests were used, and which results were combined mathematically, influence the detail of the review’s conclusions. The authors urged caution because study designs, exercise protocols and methodological quality differed.[2]
A randomized trial involving 58 women adds a more specific setting to these broad comparisons. It included 30 women with obesity and 28 without obesity, allocating participants within each population to Pilates or control groups. The program ran twice weekly for 8 weeks. Researchers assessed BMI, body fat percentage and posture, together with emotional eating, anxiety about one’s physique and self-esteem. That trial offers a way to examine whether body composition and posture followed the same pattern in different participants.[14]
Numbers: Pilates and body composition
11 randomized trials involving 393 adults with overweight or obesity: weight mean difference −2.40 kg, with a 95% confidence interval of −4.04 to −0.77 kg.[1]
The same analysis: body fat percentage mean difference −4.22 percentage points, with substantial between-study heterogeneity of 88%.[1]
12 studies involving approximately 540 adult women: weight mean difference −3.99 kg, but no significant pooled effect on body fat percentage.[2]
58 women trained twice weekly for 8 weeks: posture improved with and without obesity, while body composition results differed.[14]
19 Pilates-trained women completed 10 weeks of equipment-based exercise: core endurance improved, without an added benefit from protein supplementation.[7]
初日の汗は、予約した人だけが持ち帰れる。
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