Examining the Effectiveness of Ergonomics and Exercise Training in Caregivers

Design and setting. The trial is designed according to the Declaration of Helsinki, GoodClinical Practice guidelines, and the CONSORT 2010 statement. All assessment, education,and exercise sessions will be conducted in the environment where participants providecare (the care recipient's home) and/or in the practice areas of the affiliatedhome‐care/rehabilitation/support unit. Assessment and application areas will bestandardized (standard chair, exercise mat, and a safe environment suitable forsimulating patient transfer). The study will start only after ethics committee approvaland written informed consent.Sampling and randomization. Caregivers meeting the eligibility criteria will be enrolledby consecutive sampling. Participants will be allocated 1:1:1:1 to four groups by blockrandomization (block size 4 or 8) using a computer‐based random number generator. Therandomization list will be prepared by an independent researcher who takes no part inassessment or intervention delivery, and allocation will be concealed using sequentiallynumbered, opaque, sealed envelopes.Sample size. Sample size was calculated a priori with G*Power 3.1.9.7 for arepeated‐measures ANOVA (within‐between interaction) testing the group × time interactionof the primary outcome (ZBI) in a 4 (group) × 3 (time) mixed design, with effect size f =0.25, α = 0.05, power = 0.80, and correlation among repeated measures = 0.50. Therequired total sample was 40 (actual power 0.805). To allow balanced 1:1:1:1 blockrandomization, the minimum required sample was set at 48 participants (12 per group;power 88.7%), and with an approximately 20% allowance for expected drop‐out, a total of64 caregivers (16 per group) is planned (power 96.7%). Sensitivity analysis indicatedthat N = 48 detects f = 0.225 and N = 64 detects f = 0.193 at 80% power.Blinding. Because of the nature of the educational and exercise interventions, neitherparticipants nor the treating physiotherapist can be blinded. A single‐blind (outcomeassessor blinded) design will therefore be used: all T0, T1, and T2 assessments will beperformed by an independent physiotherapist/researcher unaware of group allocation, andthe researcher performing the statistical analysis will also be blinded to group codes(A/B/C/D).Statistical analysis. Analyses will be performed with IBM SPSS Statistics 27.0 (and R4.3, nlme/lme4, where required); two‐sided α = 0.05. Primary analyses will follow theintention‐to‐treat principle on all randomized participants, with a confirmatoryper‐protocol analysis restricted to participants attending at least 75% of sessions.Normality (Shapiro‐Wilk, skewness/kurtosis, Q‐Q plots), homogeneity of variances(Levene), equality of covariance matrices (Box's M), and sphericity (Mauchly, withGreenhouse‐Geisser or Huynh‐Feldt correction) will be examined. The primary hypothesiswill be tested through the group × time interaction of a 4 × 3 mixed‐design (repeatedmeasures) ANOVA. If clinically relevant baseline imbalance is present, ANCOVA adjustingfor T0 scores will be used. Where normality is seriously violated, data transformation ornon‐parametric alternatives (Friedman; Kruskal‐Wallis H with Dunn‐Bonferroni post hoc)will be applied. Post hoc between‐group comparisons will use Tukey HSD (or Games‐Howellif variances are unequal) and within‐group comparisons Bonferroni‐adjusted pairwisetests; Benjamini‐Hochberg false discovery rate correction will be applied to secondaryoutcomes. Dichotomous Nordic Musculoskeletal Questionnaire data will be analysed withCochran Q and McNemar tests within groups and chi‐square or Fisher's exact test betweengroups, with relative risks and odds ratios and 95% confidence intervals. Effect sizeswill be reported as partial eta squared and Cohen's d with 95% confidence intervals; forZBI, responder rates based on the minimal clinically important difference and the numberneeded to treat will also be presented.Safety. All exercise and transfer practice will be supervised by a physiotherapist onsafe flooring and according to biomechanical principles. Perceived exertion will bemonitored (Borg scale). In case of any adverse event (increased musculoskeletal pain,excessive fatigue, dizziness), the session will be modified or terminated and the eventrecorded.