Consumer wearable technology use is widespread and there is a need to validate measures obtained in uncontrolled settings. Because no standard exists for the treatment of heart rate data during exercise, the effect of different approaches on reliability (Coefficient of Variation [CV], Intraclass Correlation Coefficient [ICC]) and validity (Mean Absolute Percent Error [MAPE], Lin’s Concordance Correlation Coefficient [CCC)] were determined in the Polar Verity Sense and OH1 during trail running. The Verity Sense met the reliability (CV < 5%, ICC > 0.7) and validity thresholds (MAPE < 5%, CCC > 0.9) in all cases. The OH1 met reliability thresholds in all cases except entire session average (ICC = 0.57). The OH1 met the validity MAPE threshold in all cases (3.3–4.1%), but not CCC (0.6–0.86). Despite various heart rate data processing methods, the approach may not affect reliability and validity interpretation provided adequate data points are obtained. It is also possible that a large volume of data will artificially inflate metrics.

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PURPOSE:Inflammatory rheumatic disease (IRD) patients have attenuated muscle strength in the lower extremities, resulting in impaired physical function and quality-of-life. Although maximal strength training (MST), applying heavy resistance, is documented to be a potent countermeasure for this attenuation, it is uncertain if it is feasible in IRD patients because the population is characterized by having pain, stiffness, and joint swelling. METHODS: We randomized 23 IRD patients (49±13 years; 20females/3males), diagnosed with spondyloarthritis, rheumatoid arthritis, or systemic lupus erythematosus to MST or a control group (CG). The MST group performed four sets of four repetitions dynamic leg press two times per week for 10 weeks at ~90% of one repetition maximum (1RM). Before and after training 1RM, rate of force development (RFD), and health-related quality-of-life (HRQoL) were measured. RESULTS:The MST group increased 1RM (29±12%, p<0.001) as well as early and late phase RFD (33-76%, p<0.001-0.05) All improvements were different from the CG (p<0.001-0.05). MST also resulted in HRQoL improvements in the dimensions; physical functioning, general health, and vitality (p<0.05) with physical functioning being associated with 1RM (r=0.59, p<0.05) and early phase RFD (r=0.48-0.72, p<0.001-p<0.05; different from CG: p<0.05). CONCLUSION: Despite being characterized by pain, stiffness, and joint swelling, MST increased IRD patients´ lower extremities force generating capacity similar to previous observations in healthy individuals, and this resulted in an improvement in the patients´ HRQoL. The results suggest that MST should be considered as a treatment strategy to counteract the patients attenuated muscle strength, physical function, and quality-of-life.

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