The use of the Precor Stretch Trainer significantly improved performance on the SAR test after 30 days of flexibility training. Subjects also significantly improved performance on the Backstretch and Hamstring stretch, but not on the Butterfly stretch due to the greater subject variability. The results indicated an interrelationship among the stretches as should be expected. The greatest improvements were shown by males (vs females), individuals not involved in a stretch program prior to this program, those with low exercise levels and individuals exhibiting moderate flexibility at the onset of the stretching program. Age and stature were only moderately related to improvement.

The purpose of this project was to evaluate improved flexibility as a result of a 30 day stretching program using the Stretch Trainer.

Thirty-one subjects (age: 43.5 17.4 years, range: 36 - 61.2; mass: 73 114 kg; stature: 1.7 10.1 m) volunteered to complete a 30 day flexibility training study. An additional 10 subjects volunteered to participate in the study as a control group. The subjects were all selected from the Eugene/Springfield area. All subjects were asked to maintain their initial activity level during the 30 day stretching program. In addition, all subjects were to complete the Stretch Trainer program (all stretches) at least 5 days per week. Prior to and at the completion of the program, subjects were asked to complete a general questionnaire about their fitness program, including stretching.

Flexibility was measured prior to and following the 30 day flexibility training program. In order to assess flexibility, subjects completed a "Sit-and-Reach" (SAR) test. Additionally, to determine if the Stretch Trainer improved flexibility of specific muscle groups, the performances of three stretches were measured while the subjects were using the Stretch Trainer. The three stretches were the Back Stretch, Hamstring Stretch (both left and right sides), and the Butterfly Stretch. The training program required subjects to use the Stretch Trainer (Precor) as the mode of stretching. Flexibility of the control group was assessed twice, with each test session separated by 21-33 days.

The SAR was performed using a standard sit and reach box (Novel Products Inc., Addison, IL). Subjects placed their feet flat against the box (without shoes), kept knees straight, and with the right hand over the left, reached as far as they could on a "4-count." The SAR score represents the distance the person reached forward relative to his/her feet while sitting. A score above 23 cm indicates that the person was able to reach beyond his/her feet, and a score below 23 cm indicates that the individual could not touch his/her toes. Each subject performed the SAR test three times, and the average of the three scores was used in the analysis.

After completing the SAR tests, each subject performed the three stretches on the Stretch Trainer. Subjects were required to use the upper bar for testing purposes and to keep the legs up against the pads during all stretches where appropriate. To measure performance during the stretches, a tape measure was attached on the seat column and a horizontal straight edge was positioned on the handlebar column. The measurement between the seat column and the handle bar column (i.e. straight edge) represented the distance that the subject could stretch backwards. Measurements were recorded during the 4th and 5th repetitions (of 6 reps). Following the 3 stretches on the Stretch Trainer, the subject was retested on the SAR following the same procedures outlined above.

The training group was required to complete the flexibility training program using the Stretch Trainer program at least once per day, 5 days per week. Subjects were instructed to perform six repetitions of each stretch, and to go through all stretches at least once. Subjects were also instructed to hold each stretch (i.e. repetition) for 3 seconds. If the subjects desired to perform additional stretches, they were allowed to do so. Subjects were required to record their stretching activity daily in a Training Log.

The Stretch Trainer program consisted of 8 different stretches using a machine (the "Stretch Trainer") designed to increase flexibility. The stretches focused on increasing hamstring, lower back, and upper back flexibility. It was stressed to all subjects that the stretches should not be painful, and if there was every any sharp pain, that the stretching should be discontinued. Subjects were given written instructions as well as the corporate video instructions to use as needed. (Specific subject instructions are detailed in Appendix A). In addition, subjects were personally instructed on the proper way to perform each stretch before the program started and were further evaluated and instructed on technique after the first week of the program. All subjects were given a Stretch Trainer to use in their homes to maximize compliance.

All 31 subjects completed the flexibility training program. One subject (subject 1) did experience a muscle strain during the training program and missed 3 days. However, he was able to resume stretching (his post test SAR score improved more than the average) therefore his data were included in the analysis.

The mean and standard deviation values for the group Sit And Reach (SAR) difference scores as well as selected subgroup values are presented in Table 1 and Figure 1. Individual subject improvement scores as a function of initial flexibility are shown in Figure 2. The group SAR score improved significantly following the 30 day Precor Stretch Trainer program (F(1,21)=39.784, p<.001). The males showed a greater improvement on the SAR test than the females (F(1,21)=8.572, p=.008). The moderate stretch and low exercise subgroups exhibited greater improvements than the other comparative groups.

To determine if a subject's initial flexibility was an influencing factor on improvement, subjects were classified as having poor, moderate, or high flexibility at the beginning of the program. The criteria for grouping subjects was based on the pre SAR score. Subjects who were grouped as having poor flexibility had scores of less then 16 cm, moderate flexibility between 16 and 30 cm, and high flexibility over 30 cm. A score of 23 cm on the SAR indicated that a subject could touch his/her toes. The mean and standard deviation values for improvement on the SAR test for each of the flexibility groups are given in Table 2. The data indicate that the Moderate group showed the greatest improvement followed by the Poor and High groups.

The mean difference scores for the specific individual stretches are given in Table 3. Both the Backstretch (t(30)=5.552, p<.001) and Hamstring (t(30)=3.227, p=.003) stretches improved significantly while the Butterfly stretch did not show significant improvement (t(30)=.162, p=.872). The relationship among these three sets of test scores and the SAR scores were investigated using Pearson Product Moment Correlations (Table 4). The differences between the Post and Pre Hamstring stretches was significantly correlated with the difference between the Post and Pre SAR scores (r=0.468, p=0.008). In contrast, the difference between the Post and Pre Backstretch and Butterfly measures did not correlate with the SAR (r=-0.003, p=.987; r=0.285, p=.120). Several other data sets were also significantly correlated as shown in Table 4. These results indicate that there is an interrelationship among a number of the stretches as should be expected.

The correlation coefficients among the variables of age, level of flexibility, stature, pre SAR score, and improvement on the SAR test are given in Table 5. Flexibility was highly correlated with the pre SAR score, as should be expected. Also, the pre SAR was significantly correlated with improvement on the SAR test, though the correlation was quite low (r=-0.396, p<.05). Age and initial flexibility were negatively correlated (r=-.361, p<.05) indicating a general decrease in flexibility with age. There were no other significant correlations. Interestingly, the correlation between the level of flexibility and improvement was negatively correlated (but not significant), indicating that as a subject's initial level of flexibility increased, improvement decreased.

To further explore this relationship, a one-way ANOVA was calculated with the dependent variable being SAR improvement, and level of flexibility the independent variable. The test indicated that the level of flexibility was a significant factor (F(2,28)=11.44, p<.001) in determining the level of improvement on the SAR. The moderately flexible group improved significantly more on the SAR test compared to either the poor or high flexibility groups. The relationship between the three levels of flexibility and level of improvement is illustrated in the last three bars in Figure 1.

Figure 3 illustrates the observed improvement in the SAR Test vs Age while Figure 4 illustrates the observed improvement in the SAR Test vs Stature. In these figures, a line of reference is plotted. Any point on the line of reference indicates that that subject showed no improvement, while points above the line indicate an improvement.

The use of the Precor Stretch Trainer significantly improved performance on the SAR test after 30 days of flexibility training. Subjects also significantly improved performance on the Backstretch and Hamstring stretch, but not on the Butterfly stretch due to the greater subject variability. The results indicated an interrelationship among the stretches as should be expected. The greatest improvements were shown by males (vs females), individuals not involved in a stretch program prior to this program, those with low exercise levels and individuals exhibiting moderate flexibility at the onset of the stretching program. Age and stature were only moderately related to improvement.