Changes in the Activity of the Erector Spinae and Gluteus Medius Muscles with the Presence of Simulated Lower Limb Dysmetria.

(1) Background: Leg length discrepancy (LLD), regardless of its origin, is a very common pathology that can contribute to low back pain. Various authors have pointed out its relationship with the lack of activation of both the gluteus medius (GM) and the ipsilateral erector spinae (ES). The purpose of this study was to identify the activation of the ES and GM with different simulated LLDs, correlating this activation with LBP. In turn, we evaluated whether ES and GM activity has an effect on jumping ability using a CMJ test. (2) Method: A sample of healthy subjects was selected to whom an artificial LLD was applied using 0.5, 1, and 1.5 cm insoles. These three heights were measured using EMG while the subjects walked and performed a counter movement jump (CMJ). The measurements of the insole heights were carried out in random order using a Latin square. Muscle activation patterns were recorded for 30 s at each of the insole heights while the patients walked at 5.7 km/h and they were compared with the maximum voluntary contraction (MVC), both on the ipsilateral and contralateral sides. These muscles were then measured under the same circumstances during the performance of the CMJ. (3) Results: We found statistically significant differences in the flight heights in both the CMJ and DJ. In the comparison, significant differences were found in the flight heights of the CMJ and the DJ using the 5 mm insoles, and in the case of the DJ, also without insoles, with respect to the MVC. We found statistically significant differences in the activation of the GM with the differences in insoles, but not in the activation of the Es in relation to the different insole heights. (4) Conclusions: Insoles of different heights caused activation differences in the medius on the side where the insoles were placed. We can relate this difference in activation to LBP. In relation to the ES, no significant differences were found in the activation of the ipsilateral side of the insole.

Oxygen Uptake Slow Component and the Efficiency of Resistance Exercises.

ABSTRACT: Garnacho-Castaño, MV, Albesa-Albiol, L, Serra-Payá, N, Gomis Bataller, M, Pleguezuelos Cobo, E, Guirao Cano, L, Guodemar-Pérez, J, Carbonell, T, Domínguez, R, and Maté-Muñoz, JL. Oxygen uptake slow component and the efficiency of resistance exercises. J Strength Cond Res 35(4): 1014-1022, 2021-This study aimed to evaluate oxygen uptake slow component (V̇o2sc) and mechanical economy/efficiency in half squat (HS) exercise during constant-load tests conducted at lactate threshold (LT) intensity. Nineteen healthy young men completed 3 HS exercise tests separated by 48-hour rest periods: 1 repetition maximum (1RM), incremental-load HS test to establish the %1RM corresponding to the LT, and constant-load HS test at the LT. During the last test, cardiorespiratory, lactate, and mechanical responses were monitored. Fatigue in the lower limbs was assessed before and after the constant-load test using a countermovement jump test. A slight and sustained increase of the V̇o2sc and energy expended (EE) was observed (p < 0.001). In blood lactate, no differences were observed between set 3 to set 21 (p > 0.05). A slight and sustained decrease of half squat efficiency and gross mechanical efficiency (GME) was detected (p < 0.001). Significant inverse correlations were observed between V̇o2 and GME (r = -0.93, p < 0.001). Inverse correlations were detected between EE and GME (r = -0.94, p < 0.001). Significant losses were observed in jump height ability and in mean power output (p < 0.001) in response to the constant-load HS test. In conclusion, V̇o2sc and EE tended to rise slowly during constant-load HS exercise testing. This slight increase was associated with lowered efficiency throughout constant-load test and a decrease in jump capacity after testing. These findings would allow to elucidate the underlying fatigue mechanisms produced by resistance exercises in a constant-load test at LT intensity.

Lactate Threshold as a Measure of Aerobic Metabolism in Resistance Exercise.

In resistance training, load intensity is usually calculated as the percentage of a maximum repetition (1RM) or maximum number of possible repetitions (% of 1RM). Some studies have proposed a lactate threshold (LT) intensity as an optimal approach for concurrent training of cardiorespiratory endurance and muscle strength, as well as an alternative in resistance training. The objective of the present study was to analyze the results obtained in research evaluating the use of LT in resistance training. A keyword and search tree strategy identified 14 relevant articles in the Dialnet, Elsevier, Medline, Pubmed, Scopus and Web of Science databases. Based on the studies analyzed, the conclusion was that the LT in resistance exercises can be determined either by mathematical methods or by visual inspection of graphical plots. Another possibility is to measure the intensity at which LT might coincide with the first ventilatory threshold (VT1). Since performing an exercise session at one's LT intensity has been shown to accelerate the cardiorespiratory response and induce neuromuscular fatigue, this intensity could be used to set the training load in a resistance training program.

Exercise Prescription Using the Borg Rating of Perceived Exertion to Improve Fitness.

The present study aimed to compare two fitness-training methodologies, instability circuit resistance training (ICRT) versus traditional circuit resistance training (TCRT), applying an experimental model of exercise prescription controlling and modulating exercise load using the Borg rating of perceived exertion. Forty-four healthy young adults age (21.6±2.3 years) were randomly assigned to three groups: TCRT (n=14), ICRT (n=14) and a control group (n=16). Strength and cardiorespiratory tests were chosen to evaluate cardiorespiratory and muscular fitness before and after the training program. In cardiorespiratory data, a significant difference was observed for the time effect in VO2max, peak heart rate, peak velocity, and heart rate at anaerobic threshold intensity (p<0.05) in the experimental groups. In strength variables, a significant Group x Time interaction effect was detected in 1RM, in mean propulsive power, and in peak power (p≤0.01) in the back squat exercise. In the bench press exercise, a significant time effect was detected in 1RM, in mean propulsive power, and in peak power, and a Group x Time interaction in peak power (all p<0.05). We can conclude that applying an experimental model of exercise prescription using RPE improved cardiorespiratory and muscular fitness in healthy young adults in both experimental groups.

Cardiorespiratory and Metabolic Responses to Loaded Half Squat Exercise Executed at an Intensity Corresponding to the Lactate Threshold.

This study was designed to identify the blood lactate threshold (LT2) for the half squat (HS) and to examine cardiorespiratory and metabolic variables during a HS test performed at a work intensity corresponding to the LT2. Twenty-four healthy men completed 3 test sessions. In the first, their one-repetition maximum (1RM) was determined for the HS. In the second session, a resistance HS incremental-load test was performed to determine LT2. Finally, in the third session, subjects performed a constant-load HS exercise at the load corresponding to the LT2 (21 sets of 15 repetitions with 1 min of rest between sets). In this last test, blood samples were collected for lactate determination before the test and 30 s after the end of set (S) 3, S6, S9, S12, S15, S18 and S21. During the test, heart rate (HR) was telemetrically monitored and oxygen consumption (VO2), carbon dioxide production (VCO2), minute ventilation (VE), respiratory exchange ratio (RER), ventilatory equivalent for O2 (VE·VO2 (-1)) and ventilatory equivalent for CO2 (VE·VCO2 (-1)) were monitored using a breath-by-breath respiratory gas analyzer. The mean LT2 for the participants was 24.8 ± 4.8% 1RM. Blood lactate concentrations showed no significant differences between sets 3 and 21 of exercise (p = 1.000). HR failed to vary between S6 and S21 (p > 1.000). The respiratory variables VO2, VCO2, and VE·VCO2 (-1) stabilized from S3 to the end of the constant-load HS test (p = 0.471, p = 0.136, p = 1.000), while VE and VE·VO2 (-1) stabilized from S6 to S21. RER did not vary significantly across exercise sets (p = 0.103). The LT2 was readily identified in the incremental HS test. Cardiorespiratory and metabolic variables remained stable during this resistance exercise conducted at an exercise intensity corresponding to the LT2. These responses need to be confirmed for other resistance exercises and adaptations in these responses after a training program also need to be addressed. Key pointsIt can be identified lactate threshold at half-squat.Exercise intensity is predominantly aerobic.The duration of the half-squat can be maintained over time, ~30 min of discontinuous exercise (21 sets, 15 repetitions, 1 min rest).Lactate threshold intensity may be suitable for older adults, sedentary individuals, patients or subjects with a lower functional capacity and even for resistance sports athletes.

Effects of instability versus traditional resistance training on strength, power and velocity in untrained men.

The purpose of this study was compare the effects of a traditional and an instability resistance circuit training program on upper and lower limb strength, power, movement velocity and jumping ability. Thirty-six healthy untrained men were assigned to two experimental groups and a control group. Subjects in the experimental groups performed a resistance circuit training program consisting of traditional exercises (TRT, n = 10) or exercises executed in conditions of instability (using BOSU® and TRX®) (IRT, n = 12). Both programs involved three days per week of training for a total of seven weeks. The following variables were determined before and after training: maximal strength (1RM), average (AV) and peak velocity (PV), average (AP) and peak power (PP), all during bench press (BP) and back squat (BS) exercises, along with squat jump (SJ) height and counter movement jump (CMJ) height. All variables were found to significantly improve (p <0.05) in response to both training programs. Major improvements were observed in SJ height (IRT = 22.1%, TRT = 20.1%), CMJ height (IRT = 17.7%, TRT = 15.2%), 1RM in BS (IRT = 13.03%, TRT = 12.6%), 1RM in BP (IRT = 4.7%, TRT = 4.4%), AP in BS (IRT = 10.5%, TRT = 9.3%), AP in BP (IRT = 2.4%, TRT = 8.1%), PP in BS (IRT=19.42%, TRT = 22.3%), PP in BP (IRT = 7.6%, TRT = 11.5%), AV in BS (IRT = 10.5%, TRT = 9.4%), and PV in BS (IRT = 8.6%, TRT = 4.5%). Despite such improvements no significant differences were detected in the posttraining variables recorded for the two experimental groups. These data indicate that a circuit training program using two instability training devices is as effective in untrained men as a program executed under stable conditions for improving strength (1RM), power, movement velocity and jumping ability. Key PointsSimilar adaptations in terms of gains in strength, power, movement velocity and jumping ability were produced in response to both training programs.Both the stability and instability approaches seem suitable for healthy, physically-active individuals with or with limited experience in resistance training.RPE emerged as a useful tool to monitor exercise intensity during instability strength training.

Different Diagnostic Criteria for Determining the Prevalence of Sarcopenia in Older Adults: A Systematic Review.

Background: Sarcopenia is defined as a loss of muscle mass, strength, and physical function associated with aging. It is due to a combination of genetic, environmental, and physiological factors. It is also associated with an increased risk of health problems. Since there are many different researchers in the field, with their own algorithms and cut-off points, there is no single criterion for diagnosis. This review aims to compare the prevalence of sarcopenia according to these different diagnostic criteria in older adult populations by age group and sex. Methods: Different databases were searched: Web of Science, Pubmed, Dialnet, Scopus, and Cochrane. The keywords used were "sarcopenia", "diagnosis", "prevalence", "assessment", "aged", "aging" and "older". Studies conducted in a population aged ≥65 assessing the prevalence of sarcopenia were selected. Results: Nineteen articles met the inclusion criteria, with a total of 33,515 subjects, 38.08% female and 61.42% male, at a mean age of 74.52. The diagnostic algorithms used were 52.63% AWGS2, 21.05% EWGSOP2, 10.53% AWGS1 and EWGS1, and 5.26% FNIH. Prevalence ranged from 1.7% to 37.47%, but was higher in males and increased with age. Conclusions: The prevalence of sarcopenia varies depending on the diagnostic algorithm used, but it increases with age and is higher in men. The EWGSOP2 and AWGS2 are the most used diagnostic criteria and measure the same variables but have different cut-off points. Of these two diagnostic algorithms, the one with the highest prevalence of sarcopenia and severe sarcopenia is the AWGS2. These differences may be due to the use of different tools and cut-off points. Therefore, a universal diagnostic criterion should be developed to allow early diagnosis of sarcopenia.

Physical Activity Levels, Eating Habits, and Well-Being Measures in Students of Healthcare Degrees in the Second Year of the COVID-19 Pandemic.

BACKGROUND: When the first cases of COVID-19 (caused by SARS-CoV-2 virus infection) were discovered, exceptional norms to fight the spread of the virus were established by applying movement restrictions (lockdown) in many countries. These unprecedented norms led to sedentary behaviours and less healthy diets which could persist for much longer after lockdown. The aim of this study was to analyse the physical activity, eating habits, self-perceived well-being, and toxic habits, as well as the perceived changes of these habits with respect to the pre-pandemic period, in a population of university students in the second year of the COVID-19 pandemic. METHODS: A single-centre, cross-sectional study was conducted in a population of university students of healthcare degrees. A total of 961 students (639 (66.5%) women and 322 (33.5%) men) signed the informed consent and completed the questionnaire. The study was conducted through an anonymous survey, which was voluntarily self-completed by the students on an online platform. The questionnaire was based on the Spanish Health Survey and it was divided into six main parts: demographic and anthropometric characteristics, physical activity, eating habits, well-being measures (sleeping habits, health state, and stress), toxic habits, and perception of the influence of the COVID-19 pandemic on the variables described. RESULTS AND CONCLUSIONS: The results showed that, during the second year of the pandemic, statistically significant dependence was identified for those students that showed higher levels of physical activity with greater perceived physical activity (p < 0.05), healthier eating habits (p < 0.05), and a better self-perceived health state (p < 0.05), with respect to the 12 months before the COVID-19 pandemic. On the other hand, there was a negative correlation between the sedentary students and greater perceived physical activity (p < 0.05). With regard to toxic habits and physical activity, a significant correlation was only detected between sedentary behaviour and cocaine consumption (p < 0.05). Analysing eating habits, it was observed that the students who smoked, consumed alcohol, and binge drank had low adherence to the Mediterranean diet (p < 0.05). In addition, those students with high stress levels slept less than 7 h (p < 0.05).

The Relationship between Vegetarian Diet and Sports Performance: A Systematic Review.

INTRODUCTION: In recent years, the vegetarian diet has increased in popularity among athletes. The aim of this review is to ascertain the differences in variables related to performance, nutritional intake, and health in athletes according to whether they are omnivores or vegetarians. METHODOLOGY: A literature search was carried out in different databases: PubMed, Web of Science, Dialnet, and Cochrane. The keywords used were "vegetarian diet", "vegan diet", "exercise", "sport", and "performance". After applying different inclusion criteria, six studies were included in the review. RESULTS: No significant differences were obtained in variables related to physical performance (adherence exercise, Vo2Máx, muscle power, and sprint test) or health (body composition, psychological well-being, and social relationships), but dietary intake was significantly higher in carbohydrates and lower in proteins in vegetarian athletes (p < 0.05). CONCLUSIONS: It cannot be affirmed that vegetarian subjects have a higher sports performance, for which more research should be carried out.

Effects of Creatine Supplementation after 20 Minutes of Recovery in a Bench Press Exercise Protocol in Moderately Physically Trained Men.

BACKGROUND: The aims of this study were to analyse the effect of creatine supplementation on the performance improvement in a bench pressing (BP) strength test of muscle failure and to evaluate muscle fatigue and metabolic stress 20 min after the exercise. METHODS: Fifty young and healthy individuals were randomly assigned to a creatine group (n = 25) or a placebo group (n = 25). Three exercise sessions were carried out, with one week of rest between them. In the first week, a progressive load BP test was performed until the individuals reached the one repetition maximum (1RM) in order to for us obtain the load-to-velocity ratio of each participant. In the second week, the participants conducted a three-set BP exercise protocol against 70% 1RM, where they performed the maximum number of repetitions (MNR) until muscle failure occurred, with two minutes of rest between the sets. After one week, and following a supplementation period of 7 days, where half of the participants consumed 0.3 g·kg-1·day-1 of creatine monohydrate (CR) and the other half consumed 0.3 g·kg-1·day-1 of placebo (PLA, maltodextrin), the protocol from the second week was repeated. After each set, and up to 20 min after finishing the exercise, the blood lactate concentrations and mean propulsive velocity (MPV) at 1 m·s-1 were measured. RESULTS: The CR group performed a significantly higher number of repetitions in Set 1 (CR = 14.8 repetitions, PLA = 13.6 repetitions, p = 0.006) and Set 2 (CR = 8 repetitions, PLA = 6.7 repetitions, p = 0.006) after supplementation, whereas no significant differences were seen in Set 3 (CR = 5.3 repetitions, PLA = 4.7 repetitions, p = 0.176). However, there was a significant increase in blood lactate at minute 10 (p = 0.003), minute 15 (p = 0.020), and minute 20 (p = 0.015) after the exercise in the post-supplementation period. Similarly, a significant increase was observed in the MPV at 1 m·s-1 in the CR group with respect to the PLA group at 10, 15, and 20 min after the exercise. CONCLUSIONS: Although the creatine supplementation improved the performance in the strength test of muscle failure, the metabolic stress and muscle fatigue values were greater during the 20 min of recovery.

Is functional training an efficient approach to improve body composition in older people? A systematic review.

Introduction: Increases in fat mass and reductions in lean mass are associated with the frailty and mortality of older people. In this context, Functional Training (FT) is an option to increase lean mass and reduce fat mass in older people. Thus, this systematic review aims to investigate the effects of FT on body fat and lean mass in older people. Methods: We included randomized controlled clinical trials, with at least one intervention group that employed FT, with the age of participants ≥60 years; and participants physically independent and healthy. We performed the systematic investigation in Pubmed MEDLINE, Scopus, Web of Science, Cochrane Library, and Google Scholar. We extracted the information and used the PEDro Scale to assess the methodological quality of each study. Results: Our research found 3,056 references with five appropriate studies. Of the five studies, three presented reductions in fat mass, all of them with interventions between three and 6 months, different training dose parameters, and 100% of the sample was composed of women. On the other hand, two studies with interventions between 10 and 12 weeks presented conflicting results. Conclusion: Despite the limited literature about lean mass, it appears that long-term FT interventions may reduce fat mass in older women. Clinical Trial Registration: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=399257, identifier CRD42023399257.

Circulating nitrate-nitrite reduces oxygen uptake for improving resistance exercise performance after rest time in well-trained CrossFit athletes.

This study aimed to determine the effects of circulating nitrate plus nitrite (NOx) concentrations on resistance exercise performance, VO2 and biomarkers of muscle damage. Eleven well-trained male CrossFit athletes (29.2 ± 3.7 years, 78.9 ± 5.4 kg, 175.1 ± 6.3 cm) carried out a resistance exercise test after drinking 140 mL of beetroot juice (BJ) or placebo. The test consisted of repeating the same resistance exercise routine twice: wall ball shots plus full back squat with 3-min rest (1st routine) or without rest (2nd routine) between the two exercises. Higher NOx plasma levels were verified after BJ than placebo in the pretest and post-test (p < 0.001). A higher number of repetitions was observed after BJ intake compared to placebo in the full back squat exercise during the first routine (p = 0.004). A significantly reduced VO2 was detected after BJ intake compared to placebo during rest and full back squat execution in the first routine (p < 0.05). Plasma myoglobin concentrations were significantly increased with BJ compared to placebo (p = 0.036). These results showed that plasma NOx levels reduced VO2 after BJ intake during rest time. These reduced VO2 was a key factor for improving full back squat performance during the first routine.

Aerobic Dance on an Air Dissipation Platform Improves Cardiorespiratory, Muscular and Cellular Fitness in the Overweight and Obese Elderly.

Background: Obesity is a global health problem associated with a high number of comorbidities that decrease functional capacity, especially in elderly people. Aerobic dance is considered a viable strategy to prevent the effects of aging, mainly in obese and overweight elderly people. This study aimed to evaluate the effects of aerobic dance on an air dissipation platform (ADP) on body composition, oxidative stress and muscular and cardiorespiratory fitness in elderly people. Methods: In total, 32 elderly adults (67.1 ± 3.6) were divided into 3 groups based on body mass index: healthy (HG), overweight (OWG) and obese (OG). Training program of aerobic dance on an ADP was carried out twice a week for 12 weeks. Results: OWG (p = 0.016) and OG decreased their weight (p < 0.001). There was a significant decrease in malondialdehyde concentrations in all experimental groups (p < 0.05). OWG and OG significantly improved their peak oxygen uptake (p < 0.01). HG increased the vertical jump height (p < 0.05), and HG and OG improved the power output of the lower extremities (p < 0.05). Conclusions: The aerobic dance on an ADP may be an effective alternative to lose weight, prevent oxidative stress and improve cardiorespiratory fitness in obese and overweight elderly people.

Reproducibility and Applicability of Traditional Strength Training Prescription Recommendations.

Background: The aim of this study was to verify the reproducibility of a resistance training protocol in the bench press (BP) exercise, based on traditional recommendations, analysing the effect of the muscle fatigue of each set and of the whole exercise protocol. Methods: In this cross-sectional study, thirty male physical education students were divided into three groups according to their relative strength ratio (RSR), and they performed a 1RM BP test (T1). In the second session (T2), which was one week after T1, the participants performed a BP exercise protocol of three sets with the maximum number of repetitions (MNR) possible to muscle failure, using a relative load corresponding to 70% 1RM determined through the mean propulsive velocity (MPV) obtained from the individual load−velocity relationship, with 2 min rests between sets. Two weeks later, a third session (T3) identical to the second session (T2) was performed. The MPV of each repetition of each set and the blood lactate level after each set were calculated, and mechanical fatigue was quantified through the velocity loss percentage of the set (% loss MPV) and in a pre-post exercise test with an individual load that could be lifted at ~1 m·s−1 of MPV. Results: The number of repetitions performed in each set was significantly different (MNR for the total group of participants: set 1 = 12.50 ± 2.19 repetitions, set 2 = 6.06 ± 1.98 repetitions and set 3 = 4.20 ± 1.99 repetitions), showing high variation coefficients in each of the sets and between groups according to RSR. There were significant differences also in MPVrep Best (set 1 = 0.62 ± 0.10 m·s−1, set 2 = 0.42 ± 0.07 m·s−1, set 3 = 0.36 ± 0.10 m·s−1), which significantly reduced the % loss MPV of all sets (set 1 = 77.4%, set 2 = 64%, set 3 = 54.2%). The lactate levels increased significantly (p < 0.05) (set 1 = 4.9 mmo·L−1, set 2 = 6 mmo·L−1, set 3 = 6.5 mmo·L−1), and MPV loss at 1 m·s−1 after performing the three sets was 36% in T2 and 34% in T3, with acceptable intrasubject variability (MPV at 1 m·s−1 pre-exercise: SEM ≤ 0.09 m·s−1, CV = 9.8%; MPV at 1 m·s−1 post-exercise: SEM ≤ 0.07 m·s−1, CV = 11.7%). Conclusions: These exercise propositions are difficult to reproduce and apply. Moreover, the number of repetitions performed in each set was significantly different, which makes it difficult to define and control the intensity of the exercise. Lastly, the fatigue generated in each set could have an individual response depending on the capacity of each subject to recover from the preceding maximum effort.

Physiological Responses at 15 Minutes of Recovery after a Session of Functional Fitness Training in Well-Trained Athletes.

BACKGROUND: the aim of this study was to analyse muscle fatigue and metabolic stress at 15 min of recovery after performing two independent sessions of functional fitness training (FFT): a session of strength functional fitness training (FFTstrength) and a session of endurance functional fitness training (FFTendurance). METHODS: eighteen well-trained men conducted two protocols, separated by one week of rest: FFTstrength (3 sets of 21, 15 and 9 repetitions of Thruster with bar + Pull ups) and FFTendurance (3 sets × (30 kcal rowing + 15 kcal assault air bike)). Neuromuscular fatigue and metabolic stress were measured right before, right after and at 10 and 15 min after completing the FFT workout, as well as the mean heart rate (HRmean) and the rating of perceived exertion (RPE) at the end of the FFT. RESULTS: FFTendurance recovered the velocity loss values after 15 min of recovery. On the other hand, FFTstrength only recovered velocity in the 1 m·s-1 Tests in squat (SQ), since the velocity levels were 7% lower in the 1 m·s-1 Tests in military press exercise (MP) after 15 min. CONCLUSIONS: These data indicate that there are specific recovery patterns not only as a function of the exercise and the body regions involved, but also regarding the recovery of neuromuscular and metabolic factors, since both FFT workouts obtained high blood lactate concentrations.

Analysis of the Use and Applicability of Different Variables for the Prescription of Relative Intensity in Bench Press Exercise.

Background: The aim of the study was to analyze the use of variables such as % of one-repetition maximum (1RM) and number of maximal repetitions (xRM) with execution velocity to define and control the intensity of resistance training in bench press exercise. Hence, exercise professionals will achieve better control of training through a greater understanding of its variables. Methods: In this cross-sectional study, fifty male physical education students were divided into four groups according to their relative strength ratio (RSR) and performed a 1RM bench press test (T1). In the second test, participants performed repetitions to exhaustion (T2), using a relative load corresponding to 70% 1RM determined through the mean propulsive velocity (MPV) obtained from the individual load-velocity relationship. This same test was repeated a week later (T3). Tests were monitored according to the MPV of each repetition and blood lactate values (LACT). Results: Regarding MPV, the best (fastest) repetition of the set (MPVrep Best) values were similar between groups (0.62 m·s-1-0.64 m·s-1), with significant differences in relation to the high RSR group (p < 0.001). The average maximum number of repetitions (MNR) was 12.38 ± 2.51, with no significant differences between the RSR groups. Nonetheless, significant variation existed between groups with regards to MNR (CV: 13-29%), with greater variability in the group corresponding to the lowest RSR values (CV: 29%). The loss of velocity in the MNR test in the different groups was similar (p > 0.05). Average LACT values (5.72 mmol·L-1) showed significant differences between the Medium RSR and Very Low RSR groups. No significant differences were found (p > 0.05) between T2 and T3 with regards to MNR, MPVrep Best, or MPVrep Last, with little variability seen between participants. Conclusions: The use of variables such as the 1RM, estimated using an absolute load value, or an MNR do not allow an adequate degree of precision to prescribe and control the relative intensity of resistance training. Besides, execution velocity control can offer an adequate alternative to guarantee an accurate prescription of intensity with regard to resistance training.

The Epidemiology of Injuries in Spanish Rugby Union División de Honor.

BACKGROUND: We describe and analyze injury incidence, severity, cause of injury, anatomical location, damaged tissue, injury recurrence, and the time and place at which injuries occur over the course of a season. METHODS: An observational, descriptive, prospective, nomothetic, and multidimensional study was conducted during the 2018-2019 season with 258 players of the top semiprofessional rugby league in Spain (División de Honor de Rugby). Data were reported by the clubs' medical services. Reported time-loss injuries were collected. RESULTS: Overall exposure was 4100 h (137 matches), over 35 weeks of competition. A total of 288 injuries were reported, with three of these leading to withdrawal from the sport. A total average of 35.63 days was lost to injury. Overall time-loss injury incidence was 3.41 injuries/1000 h of exposure. Backs suffered 119 injuries corresponding to 3.80 injuries/1000 h of exposure, whilst forwards suffered 169 injuries with 4.27 injuries/1000 h of exposure. Severe injuries were the most frequent injury type. CONCLUSIONS: Outcomes confirm that more injuries take place during competition, with these also being more severe in nature. Contact injuries were most frequently suffered, above all, due to tackling or being tackled.

Effects of Capacitive-Resistive Electric Transfer on Sports Performance in Paralympic Swimmers: A Stopped Randomized Clinical Trial.

Throughout history a variety of therapeutic tools have been studied as possible enhancers of sports activities. This study proposes the use of Capacitive-Resistive Electric Transfer (CRET) as a performance booster to paralympic athletes, specifically those belonging to the Spanish Paralympic swimming committee. The study was a randomized, single-blind, and observer-blind, crossover clinical trial. Six athletes were randomly assigned to three groups: one treated with CRET (A); a placebo group (B) and a control group (C). The CRET group attended a twenty-minute session before being subjected to pool trials at distances of 50 and 100 m at maximum performance. Measurements were in two dimensions: time in seconds and the Borg scale for perceived exertion. Comparisons between groups were made with respect to distance and the main variables. In the case of perceived exertion, no significant changes were observed in any of the distances; however, in the case of the time variable, a significant difference was observed between Group A vs. Personal Record at 100 m distance (76.3 ± 6.8 vs. 68.4 ± 3.3). The proposed protocol and level of hyperthermia applied suggest refusal of CRET use for the 100-m distance a few minutes before sports practice. Our analysis suggests the need to modify the presented protocol. ClinicalTrials.gov identifier under NCT number: NCT04336007.

Match Injuries in the Spanish Rugby Union Division de Honor.

OBJECTIVE: To describe the injury rate, severity, cause, anatomical location (tissue damaged), recurrence, place and time during matches throughout a season in the Spanish Rugby Union Division de Honor. METHODS: Observational, prospective and descriptive study conducted in the competition of the Spanish División de Honor de Rugby with 258 players. The data were reported by the medical services of the previously formed clubs. RESULTS: Total exposure was 4100 h, during which 220 injuries occurred. The average number of sick days was 36.8. The total injury rate was 53.6 injuries/1000 h of exposure. Three quarters suffered 93 injuries and the forwards sustained a total of 127 injuries, with a total of 48.6 and 58.1 injuries/1000 h of exposure, respectively. Moderate injuries were the most frequent. Specifically, ligament injury was the most frequent, and dislocation was the injury that caused the most sick days. The most injuries occurred in the third quarter of the match, and the most serious injuries occurred in the second quarter. CONCLUSIONS: The injury rate of Spanish rugby competitors is 53.6 injuries/1000 match hours, with an average of 36.8 sick days. Contact injuries are the most frequent, taking place especially when tackling or being tackled.

Similar Slow Component of Oxygen Uptake and Ventilatory Efficiency between an Aerobic Dance Session on an Air Dissipation Platform and a Constant-Load Treadmill Test in Healthy Women.

There is a lack of evidence about the slow component of oxygen consumption (V.O2sc) and ventilatory efficiency (slope VE·VCO2−1) during an aerobic dance (AD) session on an air dissipation platform (ADP) despite the key role played in endurance exercises. This research was designed to assess V.O2sc, ventilatory efficiency, and blood lactate concentration by comparing two exercise modes: AD session on an ADP versus treadmill test at a constant-load intensity of the first ventilatory threshold (VT1). In the first session, an incremental treadmill test was completed. In sessions 2 and 3, the participants were randomly assigned to the AD session on an ADP or to a treadmill constant-load test at VT1 intensity to determine their cardioventilatory responses. In addition, their blood lactate levels and ratings of perceived exertion (RPE, CR-10) were evaluated. No significant differences were found between the constant-load treadmill test and AD session on an ADP with respect to V.O2sc, VE VCO2−1 slope, and RPE (p > 0.05). Higher blood lactate concentrations were observed in an AD session on an ADP than in a constant-load treadmill test at 10 min (p = 0.003) and 20 min (p < 0.001). The two different exercise modalities showed similar V.O2sc and VE·VCO2−1 slope, even though the blood lactate concentrations were different.