Ample cardiorespiratory fitness has been considered a prerequisite for walking with a prosthesis.

A study published March 22 in the journal Prosthetic and Orthotics Internationalaimed to determine cardiorespiratory fitness at the start and end of inpatient rehabilitation after lower-limb amputation as well as to determine the physical strain experienced during conventional prosthetic rehabilitation.

Researchers assessed 33 participants’ cardiorespiratory fitness using a peak one-legged cycle exercise test. Physical strain was assessed during a minimum of three full rehabilitation days using heart rate recordings. Physical strain was expressed in the time per day that heart rate exceeded 40 percent of heart rate reserve.

At the start of rehabilitation, peak aerobic capacity was on average 16.9 mL/kg/min. Overall, peak aerobic capacity did not improve over the course of rehabilitation for 23 patients, the study found. Fifty percent of the patients experienced a physical strain level that satisfied minimum criteria for maintaining cardiorespiratory fitness (greater than 40 percent heart rate reserve for 30 minutes a day).

According to the study, cardiorespiratory fitness was low and did not increase during conventional prosthetic rehabilitation. On average, the physical strain during rehabilitation was insufficient to elicit potential improvements in aerobic capacity. Study results stressed the need for dedicated physical training modules at the individual level.

Due to the results, the study’s authors suggest that clinicians need to be aware of the relatively low cardiorespiratory fitness of people who have undergone lower-limb amputation, and that improvements during rehabilitation may not always be obtained.