Effectiveness of m-health-based core strengthening exercise and health education for public safety workers with chronic non-specific low back pain: study protocol for a superiority randomized controlled trial (SAFEBACK).

BACKGROUND: Low back pain (LBP) is the leading cause of years lived with disability worldwide. Public safety workers are highly exposed to physically demanding activities and inappropriate postures, increasing the risk of experiencing LBP. Smartphone app-based self-managed interventions may be an alternative for chronic non-specific LBP (CNSLBP) treatment. This study aims to evaluate the effectiveness of a smartphone app-based self-managed exercise program plus health education, compared to a health education program alone, on neuromuscular and perceptual outcomes in police officers and firefighters with CNSLBP. METHODS: This is a parallel, two-armed, blinded evaluator randomized clinical trial. Police officers and firefighters (from public safety institutions in the Rio Grande do Sul state, Brazil) will be randomly assigned to a m-health self-managed exercise program (twice a week) plus health education or health education alone. Self-management exercise program components are mobility and core resistance exercises, available on the app. Follow-ups will be conducted post-treatment (8 weeks) and 16 weeks after randomization. The co-primary outcomes will be pain intensity and disability post-treatment (8 weeks). Secondary outcomes will be biopsychosocial factors related to CNSLBP. DISCUSSION: We hypothesize that the effects of a smartphone app-based self-managed exercise program on co-primary and secondary outcomes will be superior, compared to the health education only in public safety workers with CNSLBP. TRIAL REGISTRATION: The study was prospectively registered at ClinicalTrials.gov (NCT05481996. Registered on August 01, 2022).

High-velocity resistance training mitigates physiological and functional impairments in middle-aged and older adults with and without mobility-limitation.

The aim of the present study was to compare the neuromuscular, morphological, and functional responses to a high-velocity resistance training (HVRT) program between three cohorts: middle-aged adults (40-55 years, n = 18), healthy older adults (> 60 years, n = 18), and mobility-limited older adults (n = 8). Participants were tested before and after a 4-week control period and then assigned to a 12-week HVRT intervention. Investigated outcomes included ultrasound-derived muscle thickness and quality, maximal dynamic strength (1RM), maximal voluntary isometric contraction (MVIC), and muscle activation (sEMG), as well as muscle power and functional performance. After the intervention, quadriceps muscle thickness, 1RM, and sEMG improved in all three groups (all p < 0.05), whereas muscle quality improved only in middle-aged and older participants (p ≤ 0.001), and MVIC only in middle-aged and mobility-limited older adults (p < 0.05). With a few exceptions, peak power improved in all groups from 30-90% 1RM (p < 0.05) both when tested relative to pre-training or post-training 1RM workloads (all p < 0.05). Both mobility-limited older adults and older adults improved their short physical performance battery score (p < 0.05). Chair stand, stair climb, maximal gait speed, and timed up-and-go performance, on the other hand, improved in all three groups (p < 0.05), but no change was observed for habitual gait speed and 6-min walk test performance. Overall, our results demonstrate that a HVRT intervention can build a stronger foundation in middle-aged individuals so that they can better deal with age-related impairments at the same time that it can mitigate already present physiological and functional impairments in older adults with and without mobility-limitation.

High-intensity interval running impairs subsequent upper limb strength performance.

BACKGROUND: This study compared the effect of treadmill running on subsequent upper limb exercise performance in young men. METHODS: Seventeen young men (24.8±5.2 years) completed a: 1) bench press resistance exercise control session; 2) treadmill interval running protocol followed by the bench press session; and 3) treadmill continuous running protocol followed by the bench press session. Four sets of the bench press exercise were performed at 80% of 1RM up to volitional failure. In the interval protocol, eight sprints of 40s at 100% of the velocity of maximal oxygen uptake, with 20s of passive interval between them were performed, whereas in the continuous protocol 30-min of treadmill running at 90% of the heart rate corresponding to second ventilatory threshold was performed. The number of maximal repetitions completed in each set and condition was recorded and compared using a two-way repeated measures ANOVA. RESULTS: The interval protocol (18.7±4.9 repetitions) resulted in a reduction in the number of bench press repetitions compared to the control protocol (21.4±5.4 repetitions) (P=0.002); whereas continuous running did not affect the bench press performance (20.6±4.4 repetitions). The total number of repetitions reduced from set to set in all protocols (P<0.001). CONCLUSIONS: The results evidenced an impairment in the upper limb strength performance after high intensity interval, but not moderate intensity continuous running, which has implication for concurrent training planning and prescription.