Muscle Stiffness in Down Syndrome and Other Mentally Handicapped Subjects

Abstract

An attempt was made to determine the effects of strength training on elbow flexor stiffness of Down syndrome, non-Down syndrome mentally handicapped, and nonhandicapped subjects. It was hypothesized that stiffness would be affected by the training. Results showed that only half of the individual subjects increased their maximum voluntary contraction (MVC) level as a result of the training and that premeasures and postmeasures of MVC were not significantly different for any of the three groups. As expected, for both premeasures and postmeasures, nonhandicapped subjects had a significantly higher MVC than the other groups who were not significantly different. An important finding was that measures of stiffness (slopes of the IEMG × Torque) were not significantly different for the three groups. This finding is consistant with recent studies (Davis & Kelso, 1982; Shumway-Cook & Woollacott, in press) but raises serious doubts about the popularly held opinion that Down syndrome individuals are hypotonic. It was also found that both the Down syndrome and other mentally handicapped subjects produced significantly less torque at the maximum level than the nonhandicapped subjects. These findings suggest that deficits in mentally handicapping conditions result from a decrease in the range of a primary motor control parameter λ (see Feldman, 1986).

A systematic review on the effects of exercise programmes designed to improve strength for people with Down syndrome

“…However, the studies that investigated the effects of progressive resistance strength training 30,31 included subjects who were moderate-to-severely intellectually impaired, indicating that these individuals were capable of engaging in, and experiencing the benefits of, a strength training programme in spite of their intellectual deficits. IQ may, however, have an effect on outcome testing.…”

“…This finding has clinical implications because it suggests that these programmes can be delivered effectively in a group setting which is more cost and time efficient. Whether the programmes need to be supervised by professional personnel such as physiotherapists or human movement scientists or whether they could be conducted by trained non-professionals remains unknown as only one study 30 provided information about who ran the programme.…”

“…The type of intervention implemented also differed and included progressive resistance strength training programmes, a circuit strength training programme and a treadmill walking programme. The muscle groups targeted by training also differed from upper limb, 30 to lower limb 1 to a more generalised whole body strengthening programme. 31 Therefore, various types of strength training programmes seem to be effective for people with Down syndrome irrespective of age.…”

“…Only 3 studies 1,30,31 met the inclusion/exclusion criteria of the review and their overall quality was poor (PEDro scores of 3-5 out of 10). Two of the included studies 30,31 were non-controlled clinical trials which limits their ability to conclude that the demonstrated effects were attributed solely to the intervention implemented. Only 1 study reviewed 1 was a RCT but it mostly reported pre-and post-trial control data for activity measures (walking speed, distance and duration).…”

“…One programme 30 was administered in a group setting, another 1 as an individual programme, while the third 31 did not specify whether the programme was completed in a group or individual setting. The group intervention undertaken by Davis and Sinning 30 was supervised by graduate or undergraduate physical education majors.…”