Heart rate response and factors affecting exercise performance during home- or class-based rehabilitation for knee...

Patients undergoing total knee replacement (TKR) are typically de-conditioned and manifest medical co-morbidities associated with a lack of fitness. Consequently, an argument exists for rehabilitation programmes to target cardiovascular fitness. Doubt exists, however, as to the capacity of TKR recipients to exercise intensely and effectively. This preliminary study aimed to: (1) determine whether patients participating in a home- or class-based exercise programme can exercise in their heart rate (HR) training zone, and (2) identify confounding factors influencing performance.

A mixed method study nested within a randomized trial was undertaken. Forty-two people (mean age 70 years; 23 women) randomized to commence a 6-week group-based (GRP) or monitored home-based programme (MHP) 2 weeks post surgery participated. Assessments were undertaken weeks 5 (GRP and MHP) and 8 (GRP only) post surgery. HR and participant perceived exertion (PE, 0-10 point scale) captured exercise intensity. Qualitative description using triangulation of informant sources identified factors influencing exercise performance.

For both programmes, attainment of training HR was almost universal (93% or more), average time spent above the training HR exceeded 30 minutes, and PE indicated moderate exertion (5/10). Individual inconsistency in time spent above the training HR was evident between testing weeks in GRP participants. Therapist skill and focus, and patient co-morbidity, knee pain and stiffness and willingness were confounders of performance.

TKR recipients participating in exercise programmes can exercise moderately hard indicating a potential for rehabilitation to improve cardiovascular fitness. Whether individual fitness actually improves likely depends in part on therapist recognition of key modifiable factors. It is recommended that therapists use these observations to inform practice so patients extract the most benefit from their rehabilitation.