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).

Energy demands in high-intensity intermittent taekwondo specific exercises

Background

Taekwondo is an intermittent Olympic combat sport, which shows an aerobic predominance in matches and high participation of alactic metabolism for actions that determine competitive success. However, there is no information on energetic contribution systems in different high-intensity intermittent exercises for metabolic conditioning with specific movements. The study aimed to measure the physiological demands, mainly the energy expenditure, in taekwondo-specific high-intensity intermittent exercises (HIIE).

Methods

This study recruited ten male black belt athletes with a mean age of 20.2 ± 4 years, body mass of 62.8 ± 10.5 kg and height of 170.6 ± 7.8 cm, and total practice time of 11.8 ± 5.4 years. Subjects performed an incremental specific test and three different HIIE protocols on nonconsecutive days, and all comprised three 2-min rounds and 1 min of recovery between rounds. Heart rate, oxygen consumption, and blood lactate were measured. Energetic expenditure of aerobic, alactic, and lactic metabolisms was estimated through oxygen consumption, excess post-exercise oxygen consumption, and peak blood lactate after each round.

Results

For the mean of the three rounds, the TKDtest100 resulted in higher absolute and relative contribution from the aerobic metabolism (52.4 ± 4%; p = 0.01) and lower than the 35:5 relative alactic contribution (48.7 ± 5.4%; p = 0.03).

Conclusion

The mean of the three rounds for 35:5 and 15:10:5 presented similar absolute and relative contributions of aerobic and alactic metabolisms, whereas the TKDtest100 was a predominantly aerobic activity. We emphasize that aerobic metabolism was predominant from the second round in the 15:10:5 and 100%TKDtest protocols and in the last round of the 35:5 protocol.

Physiological aspects and energetic contribution in 20s:10s high-intensity interval exercise at different intensities

Background

One of the most popular high-intensity interval exercises is the called “Tabata Protocol”. However, most investigations have limitations in describing the work intensity, and this fact appears to be due to the protocol unfeasibility. Furthermore, the physiological demands and energetic contribution during this kind of exercise remain unclear.

Methods

Eight physically active students (21.8 ± 3.7 years) and eight well-trained cycling athletes (27.8 ± 6.4 years) were enrolled. In the first visit, we collected descriptive data and the peak power output (PPO). On the next three visits, in random order, participants performed interval training with the same time structure (effort:rest 20s:10s) but using different intensities (115%, 130%, and 170% of PPO). We collected the number of sprints, power output, oxygen consumption, blood lactate, and heart rate.

Results

The analysis of variance for multivariate test (number of sprints, power output, blood lactate, peak heart rate and percentage of maximal heart rate) showed significant differences between groups (F = 9.62; p = 0.001) and intensities (F = 384.05; p < 0.001), with no interactions (F = 0.94; p = 0.57). All three energetic contributions and intensities were different between protocols. The higher contribution was aerobic, followed by alactic and lactic. The aerobic contribution was higher at 115%PPO, while the alactic system showed higher contribution at 130%PPO. In conclusion, the aerobic system was predominant in the three exercise protocols, and we observed a higher contribution at lower intensities.

Supplementation with beta-hydroxy-beta-methylbutyrate impacts glucose homeostasis and increases liver size in trained mice

β-hydroxy-β-methyl butyrate (HMB) is a bioactive metabolite derived from the amino acid leucine, usually applied for muscle mass increase during physical training, as well as for muscle mass maintenance in debilitating chronic diseases. The hypothesis of the present study is that HMB is a safe supplement for muscle mass gain by strength training. Based on this, the objective was to measure changes in body composition, glucose homeostasis and hepatic metabolism of HMB supplemented mice during strength training. Two of four groups of male mice (n = 6/group) underwent an 8-week training period session (climbing stairs) with or without HMB supplementation (190 mg/kgBW per day). We observed lower body mass gain (4.9 ± 0.43% versus 1.2 ± 0.43, p < 0.001) and increased liver mass (40.9 ± 0.9 mg/gBW versus 44.8 ± 1.3, p < 0.001) in the supplemented trained group compared with the non-supplemented groups. The supplemented trained group had an increase in relative adipose tissue mass (12.4 ± 0.63 mg/gBW versus 16.1 ± 0.88, P < 0.01) compared to the non-supplemented untrained group, and an increase in fasting blood glucose (111 ± 4.58 mg/dL versus 122 ± 3.70, P < 0.05) and insulin resistance (3.79 ± 0.19 % glucose decay/min versus 2.45 ± 0.28, P < 0.05) comparing with non-supplemented trained group. Adaptive heart hypertrophy was observed only in the non-supplemented trained group (4.82 ± 0.05 mg/gBW versus 5.12 ± 0.13, P < 0.05). There was a higher hepatic insulin-like growth factor-1 expression (P = 0.002) in supplemented untrained comparing with non-supplemented untrained group. Gene expression of gluconeogenesis regulatory factors was increased by training and reduced by HMB supplementation. These results confirm that HMB supplementation associated with intensive training protocol drives changes in glucose homeostasis and liver metabolism in mice.

Effects of Plyometric Training on Physical Fitness in Team Sport Athletes: A Systematic Review

Plyometric training (PT) is a very popular form of physical conditioning of healthy individuals that has been extensively studied over the last decades. In this article, we critically review the available literature related to PT and its effects on physical fitness in team sport athletes. We also considered studies that combined PT with other popular training modalities (e.g. strength/sprint training). Generally, short-term PT (i.e. 2-3 sessions a week for 4-16 weeks) improves jump height, sprint and agility performances in team sport players. Literature shows that short PT (<8 weeks) has the potential to enhance a wide range of athletic performance (i.e. jumping, sprinting and agility) in children and young adult amateur players. Nevertheless, 6 to 7 weeks training appears to be too short to improve physical performance in elite male players. Available evidence suggests that short-term PT on non-rigid surfaces (i.e. aquatic, grass or sand-based PT) could elicit similar increases in jumping, sprinting and agility performances as traditional PT. Furthermore, the combination of various plyometric exercises and the bilateral and unilateral jumps could improve these performances more than the use of single plyometric drills or traditional PT. Thus, the present review shows a greater effect of PT alone on jump and sprint (30 m sprint performance only) performances than the combination of PT with sprint/strength training. Although many issues related to PT remain to be resolved, the results presented in this review allow recommending the use of well-designed and sport-specific PT as a safe and effective training modality for improving jumping and sprint performance as well as agility in team sport athletes.