Introduction: Low muscle strength is associated with an increased risk of all-cause mortality. Individuals hospitalised with COVID-19 may experience loss of muscle strength that may be reversed through rehabilitation. Our aim was to identify associations between peripheral muscle strength, exercise capacity and health related quality-of-life (HRQoL) pre- and post- COVID-19 rehabilitation.

Methods: Participants were assessed before and after a 6-week rehabilitation programme. Muscle strength (maximal isometric voluntary quadriceps contraction: MQVC), exercise capacity (incremental shuttle walk test distance: ISWT), HRQoL (EuroQol-5 Dimension-5 level: EQ-5D-5L), and Fatigue (Functional Assessment of Chronic Illness Therapy, Fatigue scale: FACIT-F) was assessed. Quadriceps weakness (QWeak) was categorised as <80% of normative MQVC value. Pearson correlation and binary logistic regression were used for analysis.

Results: We evaluated 129 participants (mean age: 54 years ± 15 years; 53.5% female). There was a positive correlation between MQVC and ISWT distance at baseline (r=0.46, p<0.01). MQVC improved 19.58% post-rehab, with males improving 14.42% (p<0.01) and females 26.01% (p<0.001). Both EQ-5D-5L and FACIT-F improved significantly (p<0.01) by mean (SD) values of +7.4 (19.42) and +5.14 (8.73), respectively. QWeak was assessed in 58 participants pre-rehab (QWeak = 74.1%) and 45 post-rehab (QWeak = 51.1%), with no association found with age, sex, BMI or length of hospital stay.

Conclusion: Quadriceps weakness was highly prevalent, with low MQVC associated with reduced exercise capacity. Rehabilitation improved MQVC, highlighting the potential for effective intervention.