The six-minute walk test (6MWT) is a widely used test for the indirect measurement of cardiorespiratory fitness in various cancer populations. Although the 6MWT is a simple test, there are no normative values for breast cancer survivors (BCS) or comparisons of results with healthy counterparts. A systematic review with a meta-analysis was carried out, which included studies from 2007 to 2020. Ninety-one studies were found, 21 of which were included in the quantitative synthesis. Among them were 9 randomized controlled trials (RCT), 8 prospective cohort studies and 4 cross-sectional studies. A total of 1084 BCS were included. Our results revealed that healthy subjects (n = 878) covered a significantly greater distance than BCS during the 6MWT (589.9 m vs. 477.4 m, p < 0.001), and the results of the meta-regression analysis showed that the 6MWD was predicted by the participants’ BMI (p < 0.001), but not by their age (p = 0.070). After adjustment for BMI, the healthy subjects also covered greater distances than the BCS (103 m; p < 0.001). The normative values of 6MWT were presented for BCS. Besides, 6MWT distances distinguish between their healthy counterparts, therefore, the 6MWT distance is a relevant parameter for the assessment and monitoring of cardiorespiratory fitness in medical and exercise interventions for BCS.

There is a lack of agreement on the efficacy of different exercise interventions in hemodialysis patients. We analyzed which exercise type is the most beneficial in terms of functional fitness and inflammation. A literature search of seven databases yielded 33 studies that met the inclusion criteria. Compared with an inactive control, the intervention group showed moderate effects (ES = 0.74; 95% CI 0.35 to 1.14; p < 0.001; and ES = 0.70; 95% CI 0.39 to 1.01; p < 0.001; respectively) on functional capacity (six-minute walk test) and oxygen consumption. Small nonsignificant effects were observed for aerobic (ES = −0.36; 95% CI −0.85 to 0.13; p = 0.154) and resistance (ES = −0.44; 95% CI −1.07 to 0.19; p = 0.169) training types, whereas moderate effects were found for combined (ES = −0.69; 95% CI −1.47 to 0.10; p = 0.088) training type based on a 10-repetition sit-to-stand test. Further, large and small effects were observed for aerobic (ES = −1.21; 95% CI −1.94 to −0.49; p = 0.001) and resistance training (ES = −0.54; 95% CI −0.90 to −0.17; p = 0.004) types on C-reactive protein. Overall, the results showed the numerically largest effect sizes for combined types compared to solely aerobic or resistance training types, with the differences between training types not reaching statistical significance. There was a significant modifying impact of age, training frequency, and session duration on performance and inflammatory outcomes.

Introduction: For patients with osteoarthritis who have undergone total knee arthroplasty (TKA), quadriceps strength is a major determinant of general physical function regardless of the parameters adopted for functional assessment. Understanding the time course of quadriceps strength recovery and effectiveness of different rehabilitation protocols is a must. Therefore, the aim of this study was to: (i) determine the magnitude of maximal voluntary strength (MVS) loss and the time course of recovery of the quadriceps muscle following TKA, (ii) identify potential moderators of strength outcomes, and (iii) investigate whether different rehabilitation practices can moderate the strength outcomes following TKA, respectively.Design: General scientific databases and relevant journals in the field of orthopedics were searched, identifying prospective studies that investigated quadriceps’ MVS pre-to post-surgery.Results: Seventeen studies with a total of 832 patients (39% males) were included. Results showed that in the early post-operative days, the involved quadriceps’ MVS markedly declined, after which it slowly recovered over time in a linear fashion. Thus, the greatest decline of the MVS was observed 3 days after TKA. When compared to pre-operative values, the MVS was still significantly lower 3 months after TKA and did not fully recover up to 6 months following TKA. Furthermore, a meta-regression analysis identified that the variables, time point of evaluation, patient age, sex, and BMI, significantly moderate the MVS of the quadriceps muscle.Conclusion: The analyzed literature data showed that the decrease in strength of the involved quadriceps muscles following TKA is considerable and lasts for several months post-surgery. Therefore, we recommend to specifically target the strengthening of knee extensor muscles, preserve motor control, and apply appropriate nutrition to ensure a holistic quadriceps muscle recovery. Since age, sex, and BMI were found to be moderating factors in patients’ recovery, further research should include specific analyses considering these moderators.

Motor imagery (MI) has been a widely used strategy in the past two decades to enhance physical capabilities among orthopaedic patients. However, its effectiveness is still questioned, since the demonstrated effects were likely task-dependent, with little evidence of transfer to tasks not specifically trained with MI. The aim of this study was to investigate whether an MI practice focused on maximal isometric knee extension strength, causes additional specific and general adaptations upon neuromuscular and functional variables when compared to conventional rehabilitation only, in patients submitted to total knee arthroplasty (TKA). Parallel group randomized controlled clinical trial. Thirty-four patients (56% man) submitted to TKA. Patients were randomly assigned to an MI practice group (MIp: 15 minutes per day/5 days per week in addition to routine physical therapy) or control group (CON) that performed routine physical therapy alone for four weeks. The maximal isometric knee extension strength of the operated leg was defined as the primary outcome. Secondary outcomes were spatial and temporal gait parameters, 30-second chair sit-to-stand performance, a self-reported physical function assessed by the Lower Extremity Functional Scale (LEFS) questionnaire, and an MI ability score. All measurements were conducted before and one month after TKA. Significant differences in treatment effects were observed for the MIp group compared to CON: the MIp showed less strength decrease (ES = 1.15, 95% CI: 0.32, 1.99, p = 0.022); faster self-selected speed under single (ES = 2.12, 95% CI: 1.16, 3.08, p = 0.001) and dual task (ES = 1.59, large, 95% CI: 0.67, 2.50, p = 0.002) conditions; brisk-pace gait speed during single (ES = 1.32, 95% CI: 0.47, 2.17, p = 0.020) and dual task conditions (ES = 1.31, large, 95% CI: 0.38, 2.23, p = 0.013); improved chair sit-to-stand (ES = 1.45, large, 95% CI: 0.58, 2.31, p = 0.004) performance; and a higher score on MI ability questionnaires for kinaesthetic imagery (KI) (ES = 0.55, 95% CI: -0.23, 1.34, p = 0.010) and internal visual imagery (EVI) (ES = 0.99, 95% CI: 0.18, 1.80, p = 0.039) scales, respectively. In addition, only MIp showed unaltered single and double support periods, as well as stride length and cadence during single task self-selected gait condition. Finally, analysis showed that the improved MI ability score achieved at the end of MI training was significantly correlated with the changes in the strength of the operated leg (kinaesthetic imagery: r = 0.741, p = 0.004; and internal visual imagery: r = 0.623, p = 0.023). MI training, when added in a corollary to routine physical therapy, led to improvements in both specific and general adaptations that were related to patients' physical capabilities. While future studies must also evaluate the long-term effects, conducting MI training during acute and post-acute rehabilitation phases is advised, especially when the extent and range of physical exercise is limited or made impossible. ClinicalTrials.gov NCT03684148.

Dynamic stability of the knee and weakness of the extensor muscles are considered to be the most important functional limitations after anterior cruciate ligament (ACL) injury, probably due to changes at the central (cortical and corticospinal) level of motor control rather than at the peripheral level. Despite general technological advances, fewer contraindicative surgical procedures, and extensive postoperative rehabilitation, up to 65% of patients fail to return to their preinjury level of sports, and only half were able to return to competitive sport. Later, it becomes clear that current rehabilitation after knee surgery is not sufficient to address the functional limitations after ACL reconstruction even years after surgery. Therefore, new therapeutic tools targeting the central neural system, i.e., the higher centers of motor control, should be investigated and integrated into current rehabilitation practice. To improve motor performance when overt movement cannot be fully performed (e.g., due to pain, impaired motor control, and/or joint immobilization), several techniques have been developed to increase physical and mental activation without the need to perform overt movements. Among the most popular cognitive techniques used to increase physical performance are motor imagery and action observation practices. This review, which examines the available evidence, presents the underlying mechanisms of the efficacy of cognitive interventions and provides guidelines for their use at home.