Effects of Aerobic Exercise Therapy through Nordic Walking Program in Lactate Concentrations, Fatigue and Quality-of-Life in Patients with Long-COVID Syndrome: A Non-Randomized Parallel Controlled Trial.

BACKGROUND: Long-COVID syndrome comprises a variety of signs and symptoms that develop during or after infection with COVID-19 which may affect the physical capabilities. However, there is a lack of studies investigating the effects of Long-COVID syndrome in sport capabilities after suffering from COVID-19 infection. The purpose of the study was to evaluate and compare lactate concentration and quality of life (QoL) in patients with Long-COVID with those who have not developed non-Long-COVID during Nordic walking exercise therapy. METHODS: Twenty-nine patients (25.5 ± 7.1 years) took part in a non-randomized controlled trial, divided into two groups: a Long-COVID group (n = 16) and a non-Long-COVID control (n = 13). Patients were confirmed as having Long-COVID syndrome if they experienced fatigue or tiredness when performing daily activities and worsening of symptoms after vigorous physical or mental activity. All participants underwent a 12-week Nordic Walking program. Lactate concentration after exercise and distance covered during all sessions were measured. Pre- and Long-Nordic Walking program, the Modified Fatigue Impact Scale (MFIS), the Short Form 36 Health Survey (SF-36), and EURO QoL-5D (EQ-ED) were administered to assess fatigue and quality of life, respectively. RESULTS: There was a lactate concentration effect between groups (F = 5.604; p = 0.024). However, there was no significant effect as a result of the session (F = 3.521; p = 0.121) with no interaction of group × session (F = 1.345; p = 0.414). The group main effect (F = 23.088; p < 0.001), time effect (F = 6.625; p = 0.026), and group × time (F = 4.632; p = 0.002) interaction on the SF-36 scale were noted. Also, there were a significant group main effect (F = 38.372; p < 0.001), time effect (F = 12.424; p = 0.005), and group × time interaction (F = 4.340; p = 0.014) on EQ-5D. However, there was only a significant group main effect (F = 26.235; p < 0.001) with no effect on time (F = 2.265; p = 0.160) and group × time (F = 1.584; p = 0.234) interaction on the MFIS scale. CONCLUSIONS: The Long-COVID group showed higher lactate concentration compared with the control group during the 12 weeks of the Nordic Walking program. The Long-COVID group presented a decrease in fatigue with respect to the control group according to the MFIS scale, as well as improvement in quality of life after aerobic exercise therapy.

Construct Validity and Test-Retest Reliability of a Free Mobile Application to Evaluate Aerobic Capacity and Endurance in Post-COVID-19 Syndrome Patients-A Pilot Study.

Introduction: Disability associated with the symptoms of post-COVID-19 syndrome is one of its main features and can have a considerable impact on care and rehabilitation units. This, linked to a decreased aerobic capacity and endurance in post-COVID-19 syndrome patients, increases interest in studying the potential of mobile applications to assess performance capacity. The purpose of this research was to study how a free mobile application assesses aerobic capacity and endurance and its relationship with aerobic capacity, test-retest reliability, and endurance evaluated by a conventional test, along with fatigue and health-related quality of life. Methods: An observational study was conducted. RUNZI®, a free mobile application, was used by mounting a Samsung Galaxy S8 smartphone using a strap on the right forearm while all participants simultaneously performed a 6-Minute Walking Test (6MWT). Construct validity between the 6MWT and the total distance performed evaluated by RUNZI® was explored. Additionally, evaluation scales to assess fatigue (MFIS) and health-related quality of life (SF-36) were used to analyze the construct validity of RUNZI®. For test−retest reliability of the app, the same instructions about the 6MWT and procedure with the app were given to all participants at two different time periods. Results: A total of 16 post-COVID-19 syndrome patients (15 females and 1 male) completed the procedure. Distance measured with the RUNZI® showed an excellent correlation with the 6MWT assessed conventionally (p < 0.0001; r = 0.851). No statistical correlations were found between the distance assessed by the RUNZI® app with MFIS and the SF-36. Test−retest reliability was found to be close to statistical significance (p = 0.058) for distance (m) measured by RUNZI® with an ICC of 0.482. Conclusions: Instrumental 6MWT assessed by the RUNZI® app for the Android® operating system showed an excellent correlation with conventional 6MWT, indicating its construct validity in post-COVID-19 syndrome patients. Further, values for the test−retest reliability for the free mobile application were close to statistical significance with a reliability considered poor in an indoor setting.

Muscle Work and Its Relationship with ACE and ACTN3 Polymorphisms Are Associated with the Improvement of Explosive Strength.

BACKGROUND: The potential influence of genetics in athletic performance allows the search for genetic profiles associated with muscular work for the orientation of strength training and sports selection. The purpose of the study was to analyze four muscular exercises for effectiveness in improving explosive strength variables, associated to the genetics in Angiotensin Converting Enzyme (ACE) and α-actinin-3 (ACTN3) polymorphisms. METHODS: A randomized controlled trial was conducted on a sample of 80 subjects allocated into four groups: concentric muscle work (CMW), eccentric muscle work (EMW), concentric-eccentric muscle (C-EMW) work and isometric muscular work (IMW), by block and gender randomization. Vertical jump, long jump, power jump, and speed were measured to study explosive strength. Genotypic frequencies of ACE (rs4646994) and ACTN3 (rs1815739) were obtained by polymerase chain reaction. RESULTS: ACE gen showed significant improvements regarding the DD genotype in the Sargent test (p = 0.003) and sprint velocity test (p = 0.017). In the ACTN3 gene, the RR variable obtained improvement results with regard to RX and XX variables in long jump (p < 0.001), Sargent test (p < 0.001) and power jump (p = 0.004). CONCLUSIONS: The selected genes demonstrated an influence on the muscle work and the improvement in explosive strength variables with a decisive role regarding the type of muscle work performed.

Effect of four different hamstring and quadriceps training protocols on explosive strength

Introduction: The main objective of this study was to analyze more effective muscle work on some explosive strength performance variables. The secondary objectives were to determine how gender influences results and influence of the muscle work type on physiological parameters.Material and methodRandomized controlled trial single-blind clinical trial, allocated by blocks and by sex.The study sample consisted of 80 healthy and active subjects divided into four muscle work groups: concentric, eccentric, concentric-eccentric and isometric.4 sets of 12 repetitions, 1-min rest between series, were performed for dynamic workgroups. For the isometric work 6s with 20 rest. 12-min time in 12 consecutive days.ResultsMain Outcomes Measures: sex, age, weight, height, body mass index, blood pressure and heart rate, jumping power, vertical jumping, horizontal jumping and speed 60m.The concentric-eccentric group achieved the best results without statistically significant differences. The men improved the speed more by 60m. Women improved in jumping power, vertical jumping and horizontal jumping. Results were statistically significant if p<0.05.ConclusionsThe group that performed the dynamic concentric-eccentric muscle work improved the performance variables analyzed further.Women are equally improved by men and heart rate dropped to the same extent. (AU)