Heart Rate Response During Underwater Treadmill Training in Adults with Incomplete Spinal Cord Injury

Background:

Walking on a submerged treadmill can improve mobility in persons displaying lower limb muscle weakness and balance deficits. Little is known, however, regarding the effect of water treadmill exercise on cardiac performance in persons with incomplete spinal cord injury (iSCI).

Objective:

To assess heart rate response during underwater treadmill training (UTT) in adults with iSCI.

Methods:

Seven males and 4 females with iSCI (age = 48 ± 13 years; 5 ± 8 years after injury) completed 8 weeks of UTT (3 sessions per week; 3 walks per session) incorporating individually determined walking speeds, personalized levels of body weight unloading, and gradual, alternating increases in speed and duration. Heart rate was monitored during the last 15 seconds of the final 2 minutes of each walk.

Results:

Over the course of 3 biweekly periods in which walking speed remained constant, heart rate fell by 7% (7 ± 1 b•min^-1; P < .001) in weeks 2 and 3, 14% (17 ± 6 b•min^-1; P < .001) in weeks 4 and 5, and 17% (21 ± 11 b•min^-1; P < .001) in weeks 6 and 7.

Conclusion:

In adults with iSCI, progressively greater absolute and relative reductions in submaximal exercise heart rate occurred after 2 months of UTT featuring a systematic increase in training volume.