Pilates in general is undeniably effective at improving fitness, but the benefits of specific methods are not so clear.

Pilates has enjoyed tremendous growth and acceptance, despite that is doesn't have the amount of research and scientific backing enjoyed by other forms of exercise,2,3 such as resistance training. It is estimated that there are almost 11 million Pilates participants in the U.S., with almost 25 percent of that number being frequent program participants. Yet many might question the validity and efficacy of the exercise form. Just how much scientific foundation does Pilates have?

Many variables to Pilates

Defining the researched effects of Pilates should start with the observation that Pilates encompasses a wide variety of equipment: reformer, trap table, Cadillac, barrel, mat and Wunda chair. Additionally, practitioners early on were almost all strict disciples of Joseph Pilates, and practiced the "classical" or full repertoire of exercises in a fashion that might have been applied by Pilates himself. Within the last five years, the neo-classical movement in Pilates has gained momentum, with instructors trying new exercises, progressions and add-on equipment.14 Thus, when viewing research, it is important to note the equipment and approach compared to results. As there are well over 500 exercises and variations that can be performed, it is difficult, from a research focus, to determine which exercises to use, as that is based on intended results and instructor philosophy.

The goal of lean muscles has been a popular rationale for participation,14,27 and involves muscular mass, shape, definition and an implied decreased level of body fat. When studied without a dietary modification program, Pilates programs have demonstrated some positive change, but not as much as reported with a more traditional resistance training program.4,6,9,10,20,21,24 "Long and lean" cannot truly be stated with empirical assurance for Pilates, but resistance training is normally attributed to an increased metabolic rate after exercise, which is a factor in body composition improvement.

New study

As Pilates is stated to improve a wide range of fitness factors, we developed a study that would use accepted, scientific measures of fitness to determine the training effects of a Pilates program. The time frame chosen was eight weeks for both the study and control group, as this would provide time for fitness changes, yet not be too demanding from a time perspective.

Subjects were previously inactive for a period of 90 days, which was defined by no more that two exercise sessions per week, formal or informal. It was felt that this would be an optimum fitness/activity level to use in the study because Pilates appeals to many previously inactive individuals as a gentle form of exercise with little discomfort. There were 13 participants in the Pilates exercise program, and six subjects in the control group, with an age range of 23 to 64 years.

Testing included height, weight, body composition using skin folds, VO2 peak and associated measures, isokinetic endurance (for eight separate muscle groups, including trunk flexion and extension), three flexibility measurements, dynamic balance, posture and self-reported stress. This was deemed to be important because Pilates has long been touted as having a mind/body benefit, with decreasing stress a potential indicator of this.

The exercise regimen was determined somewhat by the equipment; a reformer with a trampoline, as well as a jump board option, was used. This allowed participants to perform alternating periods of traditional Pilates exercises with periods of "cardio rebounding," where the reformer and the trampoline were used with a variety of single-leg and double-leg jumping patterns, with the head and back in a supported position on the reformer. As some Pilates instructors use a jump board in this fashion, it was determined a reasonable exercise inclusion and strategy.

Total exercise time was 40 minutes per session, with three sessions per week. All instructors either had Peak Pilates or P.M.A. certifications. Exercise order was slightly modified from a traditional Pilates program to allow the participants to work efficiently within five-minute blocks. During the first three weeks, no specific stretching exercises were used, with three to four stretches used in the last five minutes of week four onward. Both groups were given basic dietary information on such subjects as the importance of hydration, the role of breakfast, not skipping meals and other easy-to-follow guidelines.

During the study, two sub-studies were undertaken. The first component was to compare the energy expenditure of "cardio-rebounding" to conventional treadmill walking or elliptical use. This was performed in the fifth week of the study to ensure participants had familiarity with the jumping movements, and would not have higher energy expenditure because the exercise was novel. Participants were asked to perform each exercise at an aerobic level of six (out of 10), based on rate of perceived exertion. The second component was to assess blood pressure response to this type of exercise compared to steady-state treadmill and elliptical exercise. (During rebounding, legs are above the plane of the upper body, and there may be blood pressure responses that negate participation from individuals with hypertensive issues.)

Research results

After the eight-week program, parametric and independent samples revealed statistically significant (p<0.05) gains and improvements in VO2 (17 percent), anaerobic threshold (25 percent), body fat improvement/decrease (15 percent), gain in lean mass (5 percent), decrease in fat weight (17 percent), overall stress decrease (73 percent), low-back/hamstring flexibility (202 percent), combined hip flexion (8 percent) and combined torso rotation (23 percent). Overall strength/endurance improved (28 percent), as well as performance on the chest press (24 percent, which was actually a p=0.06), row (22 percent), knee extension (14 percent), knee flexion (12 percent), shoulder press (33 percent), lat pull down (28 percent), abdominal crunch (33 percent), back extension (57 percent) and overall strength/endurance to body weight ratio (30 percent).

The first sub-study on the actual kcal per minute of cardio rebounding versus treadmill walking or using a leg-only elliptical revealed that the cardio rebounding activity used slightly more energy per minute than either the treadmill or elliptical activity. The second sub-study had consistent peak systolic pressures under 160 mmHg, while mean blood pressure was consistently below 120 mmHg.

Discussion/Implications

Clearly, Pilates increases core endurance,15,16,22 and the ability to contract the transversus abdominis8 compared to traditional core training. In a related area, limited research has pointed to the result that long-term Pilates training can positively affect posture and balance, mostly from carrying the upper body weight in a better fashion via better hip and back alignment,11,12,18,28 yet not necessarily more effectively than other training methods.4,11 Caution should be used when stating posture benefits from Pilates, as measurement and grading concepts are not standardized, even though, in visual assessment of each subject, there was clearly better posture after the training regimen.

This new study showed similar increases in trunk flexion and extension abilities to a previous study.25 One of the surprising findings was that the regimen used demonstrated increases in the strength endurance of all the major muscle groups used in testing. Because each testing bout measured total force produced over 20 repetitions, it is not surprising that an activity that repeatedly targets key muscle groups would produce this result. However, the testing movements compared to the actual exercise movements were very different, so there was little chance for movement carryover, only increased muscular endurance. As many people need this ability for activities of daily living, this study provides one instance where Pilates increases strength endurance. As peak torque for one maximal voluntary contraction was not measured, our speculation is that the loads used in Pilates, being sub-maximal and endurance-oriented, would not have elicited much increase in this ability.

It was not surprising that, in this study, flexibility increased, but rather the level of change. Hip flexion showed minor improvements, yet that may have been due to the fact that the subjects were close to normal before exercise. Sit and reach flexibility gained tremendously, probably due to the low-back and hamstring movements normally used in Pilates. The ability to twist along the spinal axis as measured by a torso rotation test increased greatly, which not only translates into better activities of daily living, but to certain sports performance, such as tennis. Like previous studies with flexibility measures,1,5,20 the flexibility gained is specific to the exercises used.

In this study, mat Pilates was used, and energy expenditure and heart rate were below ACSM guidelines. It may be that the unfit and non-accustomed Pilates participant has a much higher energy expenditure simply because lack of strength and control leads to using more muscular force and energy than necessary. Traditional Pilates exercise has an energy expenditure level that can, at best, be classified as moderate, or a walking speed on a treadmill of 4 to 4.5 miles per hour.19 In one study of an acute training session, heart rate did not reach what is normally considered a training level or zone.24

Also in this study, the cardio rebounding component was slightly better. Using a trampoline device on the end of the reformer in a supported jumping movement had a much higher energy expenditure, equal to or surpassing the level of energy expenditure on a treadmill or elliptical at a prescribed intensity.28 This was significantly higher than for standard Pilates exercises, which may be because in this particular study, body composition and weight-loss improvements were significant compared to other investigations. Since other reformers have a jump board option, it is not clear whether a jump board used in the same fashion would produce a similar energy expenditure result.

In terms of stress levels, in this study, the subjects maintained the same job, responsibilities and social activities for the eight weeks. So, it was surprising that their perceived level of stress was lower after completing the training program, pointing to the Pilates regimen as the primary cause for decreased levels of self-perceived stress. There is virtually no other research that points to states of relaxation, arousal, tension and post-exercise levels that support the notion of "mindfulness."

While this study clearly demonstrates that Pilates increases a wide variety of fitness variables, additional research insights are needed to further define the benefits compared to specific Pilates methods.

References available upon request at edit@fitnessmanagement.com.