Efficacy of Split Versus Full-Body Resistance Training on Strength and Muscle Growth: A Systematic Review With Meta-Analysis.

ABSTRACT: Ramos-Campo, DJ, Benito-Peinado, PJ, Caravaca, LA, Rojo-Tirado, MA, and Rubio-Arias, JÁ. Efficacy of split versus full-body resistance training on strength and muscle growth: a systematic review with meta-analysis. J Strength Cond Res 38(7): 1330-1340, 2024-No previous study has systematically compared the effect of 2 resistance training routines commonly used to increase muscle mass and strength (i.e., split [Sp] and full-body [FB] routines). Our objective was to conduct a systematic review and meta-analysis following PRISMA guidelines to compare the effects on strength gains and muscle growth in healthy adults. 14 studies (392 subjects) that compared Sp and FB routines in terms of strength adaptations and muscle growth were included. Regarding the effects of the Sp or FB routine on both bench press and lower limbs strength, the magnitude of the change produced by both routines was similar (bench press: mean difference [MD] = 1.19; [-1.28, 3.65]; p = 0.34; k = 14; lower limb: MD = 2.47; [-2.11, 7.05]; p = 0.29; k = 14). Concerning the effect of the Sp vs. FB routine on muscle growth, similar effects were observed after both routines in the cross-sectional area of the elbow extensors (MD = 0.30; [-2.65, 3.24]; p = 0.84; k = 4), elbow flexors (MD = 0.17; [-2.54, 2.88]; p = 0.91; k = 5), vastus lateralis (MD = -0.08; [-1.82, 1.66]; p = 0.93; k = 5), or lean body mass (MD = -0.07; [-1.59, 1.44]; p = 0.92; k = 6). In conclusion, the present systematic review and meta-analysis provides solid evidence that the use of Sp or FB routines within a resistance training program does not significantly impact either strength gains or muscle hypertrophy when volume is equated. Consequently, individuals are free to confidently select a resistance training routine based on their personal preferences.

The ergogenic effects of acute carbohydrate feeding on endurance performance: a systematic review, meta-analysis and meta-regression.

A systematic review with meta-analysis was conducted to analyze the effect of carbohydrate (CHO) intake during exercise and some variables that could moderate this effect on endurance performance. We included 136 studies examining the effect of CHO ingestion during endurance exercise in the meta-analysis. The overall effect on performance showed a significant increase after CHO intake compared to the placebo/control groups. A larger effect of CHO consumption is observed in time to exhaustion than in time trials performance test. Moreover, the effectiveness of CHO supplementation was greater the longer the duration of the events. Also, there seems to be a higher effect of CHO intake in lower trained than in higher trained participants. In contrast, the magnitude of performance change of CHO intake is not affected by the dosage, ergometer used, the type of intake of the CHO ingestion and the type of CHO. In addition, a lower rate of perceived exertion and higher power and heart rate are significantly associated with the ingestion of CHO during endurance exercise. These results reinforce that acute CHO feeding is an effective strategy for improving endurance performance, especially, in less trained subjects participating in time to exhaustion tests of longer durations.

Lateral wedge insoles and their use in ankle instability.

The aim of the present study is to assess the immediate effects of applying lateral wedge insoles of different heights (0.00, 0.3, 0.4, and 0.6 cm) in patients with chronic ankle instability (CAI) in normal and supinated feet during a Star Excursion Balance Test (SEBT) and in the reflex response of Peroneus Longus (PL), Peroneus Brevis (PB), and Tibialis Anterior (TA) over a 30° inversion of the feet. The effects of the height of the wedges were assessed using a double-blind, crossover design. In total, 25 participants were allocated into two groups, depending on the foot posture (Normal = 12, Supinated = 13) and performed the tests in a random fashion. Reaction time (RT) of stabilizing muscles of the ankle was measured using superficial electromyography (EMG) and postural balance with the SEBT. Foot posture did not show any significant effects on the analyzed variables. Nonetheless, the use of a 0.3 cm external rearfoot wedge (PB p = 0.002; PL p = 0.066 and TA p = 0.006) and 0.6 cm (PB p = 0.043; PL p = 0.058 and TA p = 0.071) reduces RT in stabilizing muscles of the ankle and improves results in SEBT, except for the anterolateral direction, in subjects with CAI. Therefore, our results suggest that the use of lateral wedge insoles could reduce RT and improve dynamic balance in chronic ankle instability.

Effects of fast-velocity concentric resistance training in people with multiple sclerosis: A randomized controlled trial.

OBJECTIVES: To analyze the effects of a fast-velocity concentric resistance training (FVCRT) program on maximum strength of upper and lower limb, gait speed, walking endurance, fatigue, physical self-perception, and catastrophizing pain in people with multiple sclerosis (MS). MATERIALS AND METHODS: Participants were randomized to either an experimental [EG] (n = 18) or a control [CG] (n = 12) group. The EG carried out 10-weeks of lower limb FVCRT. The CG did not perform any intervention. The maximum isometric voluntary contraction (MVIC) during knee extension, hand-grip strength, gait speed, walking endurance, fatigue, physical self-perception, and catastrophizing pain were measured. RESULTS: Inter-group differences after intervention were found on the right and left sides in MVIC (p = .032; ES = -0.7 and p = .009; ES = -0.9), and hand grip strength (p = .003; ES = -1.0 and p = .029; ES = -0.7). After FVCRT, there was in increase in MVIC (p < .001; ES = -1.7 and p < .001; ES = -1.3) and hand grip strength (p < .001; ES = -1.3 and p < .001; ES = -1.3) on both right and left sides, respectively. In addition, gait speed (p = .023; ES = 1.3), walking endurance (p < .001; ES = -1.0), symptomatic fatigue (p = .004; ES = 0.6), and catastrophizing pain (p < .001; ES = 1.0) improved in EG. CONCLUSION: Lower limb FVCRT improved the upper and lower limb strength, walking, symptomatic fatigue, and catastrophizing pain in MS participants.

Dosage and Effectiveness of Aerobic Training on Cardiorespiratory Fitness, Functional Capacity, Balance, and Fatigue in People With Multiple Sclerosis: A Systematic Review and Meta-Analysis.

OBJECTIVES: To evaluate the benefits of aerobic training (AT) programs on cardiorespiratory fitness, functional capacity, balance, and fatigue in individuals with multiple sclerosis (MS) and to identify the optimal dosage of AT programs for individuals with MS via a systematic review with meta-analysis. DATA SOURCES: Two electronic databases were searched until March 2020 (PubMed-Medline and Web of Science). STUDY SELECTION: Studies examining the effect of AT program on cardiorespiratory fitness, functional capacity, balance, and fatigue were included. DATA EXTRACTION: After applying the inclusion and exclusion criteria, we included 43 studies. A total sample of 1070 individuals with MS (AT group, n=680; control group, n=390) were analyzed. DATA SYNTHESIS: The AT group demonstrated a significant increase in cardiorespiratory fitness (standardized mean difference [SMD], 0.29; P=.002), functional capacity (timed Up and Go Test: SMD, -1.14; P<.001; gait speed: SMD, -1.19; P<.001; walking endurance: SMD, 0.46; P<.001), and balance (SMD, 3.49; P<.001) after training. Fatigue perception also decreased (SMD, -0.45; P<.001). However, no significant differences were observed when compared with the control group in either cardiorespiratory fitness (SMD, 0.14; P=.19) or fatigue perception. Nevertheless, we observed significant differences between the AT and control groups in balance (P=.02), gait speed (P=.02), and walking endurance (P=.03), favoring the participants who performed AT. Regarding the subgroup analysis, no significant differences were observed between subgroups in any of the variables studied except for gait speed, for which a greater increase in posttraining was observed when the AT program applied the continuous method (χ2=7.75; P=.005) and the exercises were performed by walking (χ2=9.36; P=.002). CONCLUSIONS: Aerobic training improves gait speed, walking endurance, and balance. Cardiorespiratory fitness and fatigue perception also improved after AT, but we found no differences with the control group. In addition, subgroup analysis suggested that training using continuous and walking methods could optimize gait speed.

Effects of Whole-Body Vibration Training on Body Composition, Cardiometabolic Risk, and Strength in the Population Who Are Overweight and Obese: A Systematic Review With Meta-analysis.

OBJECTIVES: To assess the effects of whole-body vibration training (WBVT) on body composition, metabolic and cardiovascular risk variables, and lower limb strength in participants who are overweight/obese. DATA SOURCES: A systematic review with meta-analysis was conducted in 3 databases (PubMed-MEDLINE, Web of Science, and Cochrane Library) from inception through to January 26, 2020. STUDY SELECTION: Studies analyzing the effect of WBVT on body composition variables, metabolic profile, blood pressure, heart rate, and lower limb strength in the population who are overweight/obese, with interventions of a minimum length of 2 weeks were included. DATA EXTRACTION: After applying the inclusion and exclusion criteria, 23 studies involving 884 participants who were obese/overweight (experimental group: 543; weight=79.9 kg; body mass index (BMI) =31.3 kg/m2, obesity class I according to World Health Organization) were used in the quantitative analysis. The sex of the participants involved in the studies were as follows: (1) 17 studies included only female participants; (2) 1 study included only boys, and (3) 5 studies included both sexes. Meta-analysis, subgroup analysis, and meta-regression methods were used to calculate the mean difference and standardized mean difference (SMD; ± 95% confidence intervals [CIs]) as well as to analyze the effects of pre-post intervention WBVT and differences from control groups. DATA SYNTHESIS: WBVT led to a significant decrease in fat mass (-1.07 kg, not clinically significant). In addition, WBVT reduced systolic blood pressure (-7.01 mmHg, clinically significant), diastolic blood pressure (-1.83 mmHg), and heart rate (-2.23 bpm), as well as increased the lower extremity strength (SMD=0.63; range, 0.40-0.86). On the other hand, WBVT did not modify the weight, BMI, muscle mass, cholesterol, triglycerides, or glucose. CONCLUSIONS: WBVT could be an effective training modality to reduce blood pressure (clinically relevant) and resting heart rate. In addition, WBVT led to improved lower limb strength. However, these findings were not consistent with significant improvements on other variables associated with metabolic syndrome (body composition, cholesterol, triglycerides, glucose).

Effects of whole-body vibration training on calf muscle function during maximal isometric voluntary contractions.

The purposes of this study were to determine the impact of 6 weeks of whole-body vibration training (WBVT) on maximum voluntary plantar flexor strength, muscle activity via surface electromyography (EMG), and muscle architecture measured at rest and during maximal contraction at different ankle joint angles in young healthy adults. Using a single-blind study design, 28 healthy men and women were randomly assigned to control (CG; N = 14, 7 women) or whole-body vibration training (WBVG; N = 14, 7 women) groups. Vibration training (20-25 minutes; standing with knees flexed) was performed 3 week-1 for 6 weeks (18 sessions). Maximum isometric plantar flexor torque, muscle activity (medial and lateral gastrocnemius EMG) and medial gastrocnemius fascicle angle and length at rest and maximum contraction were tested at four ankle joint angles (ranging 45° to -15°; 0° = anatomical) before and after training. Significant increases (24.7%-37.5%) were observed in peak torque (N∙m∙kg-1 ;%) at -15°, 0°, 15° and 30° joint angles from pre- to post-intervention in WBVG, which were different to CG (no change) and greater at longer muscle lengths. No between-group differences were observed in changes in EMG amplitudes measured during contraction or muscle architecture parameters at rest or during contraction. Six weeks of WBVT in young, healthy adults increased isometric plantarflexion strength at multiple joint angles, without detectible changes in EMG, muscle architecture, or body composition. Therefore, WBVT can significantly improve maximum plantar flexor strength at multiple joint angles (muscle lengths) in young healthy men, although the mechanisms underpinning the changes are currently unclear.

Neuromuscular and Mobility Responses to a Vibration Session in Hypoxia in Multiple Sclerosis.

The aim of this study was to investigate the acute effects of vibration training (WBVT) under hypoxic and normoxic conditions on the voluntary rate of force development (RFD), balance and muscle oxygen saturation (SMO2) in persons with Multiple Sclerosis (MS). 10 participants completed the study (30% males, 44.4±7.7 years, 164.3±8.9 cm, 65.2±11.1 kg, 2.5±1.3 Expanded Disability Status Scale, 24.1±4.0 kg.m-2 BMI). Maximal force, RFD during isometric knee extension, static balance with eyes open and closed and sit-to-stand test were evaluated before and immediately after one session of WBVT (12 60-s bout of vibration; frequency 35 Hz; amplitude 4 mm; 1-min rest intervals) under both normoxic and hypoxic conditions. In addition, SMO2 of the gastrocnemius lateralis was assessed during each condition. No changes were found in force, static balance and sit-to-stand test. Time-to-peak RFD increased in the left leg (p=0.02) and tended to increase in the right leg (p=0.06) after the hypoxic session. SMO2 resulted in significant increases from the initial to final intervals of the WBVT under both hypoxic and normoxic conditions (p<0.05). Increases in SMO2 during WBVT demonstrates muscle work that may contribute to the observed muscle adaptations in long-term WBVT programs without inducing decreases in neuromuscular activation, physical function and balance within a session.

Exercise-Induced Muscle Damage During the Menstrual Cycle: A Systematic Review and Meta-Analysis.

ABSTRACT: Romero-Parra, N, Cupeiro, R, Alfaro-Magallanes, VM, Rael, B, Rubio-Arias, JA, Peinado, AB, and Benito, PJ, IronFEMME Study Group. Exercise-induced muscle damage during the menstrual cycle: A systematic review and meta-analysis. J Strength Cond Res 35(2): 549-561, 2021-A strenuous bout of exercise could trigger damage of muscle tissue, and it is not clear how sex hormone fluctuations occurring during the menstrual cycle (MC) affect this response. The aims of this study were to systematically search and assess studies that have evaluated exercise-induced muscle damage (EIMD) in eumenorrheic women over the MC and to perform a meta-analysis to quantify which MC phases display the muscle damage response. The guidelines of the Preferred Reported Items for Systematic Reviews and Meta-Analysis were followed. A total of 19 articles were analyzed in the quantitative synthesis. Included studies examined EIMD in at least one phase of the following MC phases: early follicular phase (EFP), late follicular phase (LFP), or midluteal phase (MLP). The meta-analysis demonstrated differences between MC phases for delayed onset muscle soreness (DOMS) and strength loss (p < 0.05), whereas no differences were observed between MC phases for creatine kinase. The maximum mean differences between pre-excercise and post-exercise for DOMS were EFP: 6.57 (4.42, 8.71), LFP: 5.37 (2.10, 8.63), and MLP: 3.08 (2.22, 3.95), whereas for strength loss were EFP: -3.46 (-4.95, -1.98), LFP: -1.63 (-2.36, -0.89), and MLP: -0.72 (-1.07, -0.36) (p < 0.001). In conclusion, this meta-analysis suggests that hormone fluctuations throughout the MC affect EIMD in terms of DOMS and strength loss. Lower training loads or longer recovery periods could be considered in the EFP, when sex hormone concentrations are lower and women may be more vulnerable to muscle damage, whereas strength conditioning loads could be enhanced in the MLP.

Muscle Architecture and Neuromuscular Changes After High-Resistance Circuit Training in Hypoxia.

ABSTRACT: Ramos-Campo, DJ, Martínez-Guardado, I, Rubio-Arias, JA, Freitas, TT, Othalawa, S, Andreu, L, Timón, R, and Alcaraz, PE. Muscle architecture and neuromuscular changes after high-resistance circuit training in hypoxia. J Strength Cond Res 35(11): 3035-3040, 2021-This study aimed to analyze the effect of 8 weeks of high-resistance circuit (HRC) training in hypoxia on muscle architecture, strength, and neuromuscular variables. Twenty-eight resistance-trained subjects were assigned to a hypoxia (FiO2 = 15%; HG: n = 15; age: 24.6 ± 6.8 years; height: 177.4 ± 5.9 cm; and mass: 74.9 ± 11.5 kg) or normoxia group (FiO2 = 20.9%; NG: n = 13; age: 23.2 ± 5.2 years; height: 173.4 ± 6.2 cm; and mass: 69.4 ± 7.4 kg). Each training session consisted of 2 blocks of 3 exercises (block 1: bench press, leg extension, and front lat pulldown; block 2: deadlift, elbow flexion, and ankle extension). Each exercise was performed with a 6 repetition maximum load. Subjects exercised twice weekly and, before and after the training program, vastus lateralis muscle thickness and pennation angle, knee extensors electromyographic activity, maximum voluntary contraction (MVC), and rate of force development (RFD) and H-Reflex (Hmax), M-wave of the soleus muscle were assessed. Both training groups showed similar improvements in muscle thickness (effect size [ES] = HG: 0.23; NG: 0.41), pennation angle (ES = HG: 0.86; NG: 0.15), MVC (ES HG: 0.63; NG: 0.61), Hmax (ES = HG: 0.96; NG: 0.40), RFD at 200 milliseconds (ES = HG: 0.31; NG: 0.61) and peak RFD (ES = HG: 0.21; NG: 0.66). No significant between-group differences were found. In conclusion, similar morphological and neuromuscular adaptations can be achieved after 8 weeks of HRC training under hypoxic or normoxic conditions.

Complex and Contrast Training: Does Strength and Power Training Sequence Affect Performance-Based Adaptations in Team Sports? A Systematic Review and Meta-analysis.

Cormier, P, Freitas, TT, Rubio-Arias, JÁ, and Alcaraz, PE. Complex and contrast training: Does strength and power training sequence affect performance-based adaptations in team sports? A systematic review and meta-analysis. J Strength Cond Res 34(5): 1461-1479, 2020-The aims of this meta-analysis were to examine the effects of 2 different strength and power training sequences (complex: CPX; and contrast: CNT, training) on performance-based adaptations in team sports {lower-body strength (1 repetition maximum [1RM]), vertical jump (VJ), sprinting, and change of direction (COD) ability}, as well as identify factors potentially affecting said adaptations (i.e., athlete level, type of sport, intensity, and duration). CPX is the combination training that alternates biomechanically similar high load weight training exercises with lighter load power exercises, set for set (e.g., squats followed by countermovement jumps). CNT is the combination training where all high load strength exercises are performed at the beginning of the session and all lighter load power exercises at the end. After an electronic database search (PubMed, SPORTDiscus, and WoS), a total of 27 articles were included in the meta-analysis. The effects on outcomes were expressed as standardized mean differences (SMDs). Baseline to postintervention overall results for the studied variables: (a) 1RM: large effects for CPX (SMD = 2.01, 95% confidence interval [CI] 1.18-2.84) and CNT (SMD = 1.29, 95% CI 0.61-1.98); (b) VJ: large effects for CPX (SMD = 0.88, 95% CI 0.42-1.34) and medium effects for CNT (SMD = 0.55, 95% CI 0.29-0.81); (c) sprint: large effects for CPX (SMD = -0.94, 95% CI -1.33 to -0.54) and small effects for CNT (SMD = -0.27, 95% CI -0.92 to 0.39); and (d) COD: large effects for CPX (SMD = -1.17, 95% CI -1.43 to -0.90) and medium effects for CNT (SMD = -0.68, 95% CI -1.20 to -0.15). Regarding the studies that contained a control group: (a) 1RM: large effects for CPX (SMD = 1.61, 95% CI 1.12-2.10) and CNT (SMD = 1.38, 95% CI 0.30-2.46); (b) VJ: large effects for CPX (SMD = 0.85, 95% CI 0.45-1.25) and medium for CNT (SMD = 0.50, 95% CI 0.19-0.81); (c) sprint: medium effects for CPX (SMD = -0.69, 95% CI -1.02 to -0.36) and CNT (SMD = -0.51, 95% CI -0.90 to -0.11); and (d) COD: large effects for CPX (SMD = -0.83, 95% CI -1.08 to -0.59), and there were no control groups for CNT. In conclusion, both training interventions may lead to positive performance-based adaptations in team-sports with CPX interventions potentially leading to slightly greater effects.

Eating Disorders in Pregnant and Breastfeeding Women: A Systematic Review.

Background: Pregnancy is a stage associated with various biopsychosocial changes. These changes, along with concerns about keeping an adequate weight, can modulate an individual's risk for psychological disorders, especially eating disorders (EDs). The aim of this review was to investigate the prevalence, associated risks, and consequences of eating disorders in pregnancy and in breastfeeding mothers. Materials and Methods: A systematic review was carried out following the PRISMA guidelines in the scientific databases: PubMed, Web of Science, Scopus, and PsycINFO. Search terms related to EDs, pregnancy, and breastfeeding were used. The evaluation of the methodological quality of the studies was carried out using different scales; CASP (Checklist for Cohort Study), NICE (Methodology Checklist for Cohort Study), ARHQ (Methodology Checklist for Cross-Sectional), and NOS (Newcastle-Ottawa Scale for Cohort). Results: From 2920 studies, 16 were selected to study EDs in pregnant women and 2 studies in nursing mothers. Most of the studies used questionnaires and scales as tools for the diagnosis of EDs. Binge eating, anxiety, and depression were the most common comorbidities of EDs, accompanied in most cases by excessive concern about weight gain. The consequences of EDs are diverse. The prevalence of EDs in this population is estimated to be 1 out of 20. Conclusions: Eating disorders are related to anxiety and depression and have negative consequences for both mothers and fetuses (cesarean, miscarriages, premature births). More research on the field to determine the risk factors for EDs in the population of pregnant and lactating women is needed.

Morphological and Physical Fitness Profile of Young Female Sprint Kayakers.

López-Plaza, D, Alacid, F, Rubio, JÁ, López-Miñarro, PÁ, Muyor, JM, and Manonelles, P. Morphological and physical fitness profile of young female sprint kayakers. J Strength Cond Res 33(7): 1963-1970, 2019-Traditionally, physical and anthropometrical profiles of the most successful kayak athletes have been identified in male kayakers. This study attempted to identify the differences in morphology and fitness level of 2 performance-based groups of young elite female paddlers. Eighty-six female kayakers, aged 13.62 ± 0.57 years (mean ± SD), were allocated in 2 groups (Top-10 and Rest) depending on their ranking in the 3 Olympic distances (200, 500, and 1,000 m). All subjects underwent a battery of anthropometrical (heights, mass, girths, and sum of skinfolds), physical fitness (overhead medicine ball throw, countermovement jump, sit-and-reach test, and 20-m multistage shuttle run test), and specific performance assessments (200, 500, and 1,000 m). Best paddlers presented significantly greater anthropometrical values in muscle mass percentage, maturity status, and chronological age (p ≤ 0.05), whereas physical fitness comparison only revealed significant differences in countermovement jump (p ≤ 0.05). Furthermore, aerobic power and muscle mass percentage seem to be crucial in achieving optimal performances at long (1,000 m) and short duration races (200 and 500 m). These findings confirm the importance of a larger and compact morphology, as well as superior fitness level, for success in female kayakers. The current results not only identify the weak areas on body composition and physical fitness depending on the maturity status but also the development of specific training programs for females.

Biochemical responses and physical performance during high-intensity resistance circuit training in hypoxia and normoxia.

PURPOSE: The aim of this study was to analyze the effect of hypoxia on metabolic and acid-base balance, blood oxygenation, electrolyte, and half-squat performance variables during high-resistance circuit (HRC) training. METHODS: Twelve resistance-trained subjects participated in this study. After a 6RM testing session, participants performed three randomized trials of HRC: normoxia (NORM: FiO2 = 0.21), moderate hypoxia (MH: FiO2 = 0.16), or high hypoxia (HH: FiO2 = 0.13), separated by 72 h of recovery in normoxic conditions. HRC consisted of two blocks of three exercises (Block 1: bench press, deadlift and elbow flexion; Block 2: half-squat, triceps extension, and ankle extension). Each exercise was performed at 6RM. Rest periods lasted for 35 s between exercises, 3 min between sets, and 5 min between blocks. Peak and mean force and power were determined during half-squat. Metabolic, acid-base balance, blood oxygenation and electrolyte variables, arterial oxygen saturation (SaO2), and rating of perceived exertion (RPE) were measured following each block. RESULTS: During the first set, peak force and power were significantly lower in HH than MH and NORM; whereas in the second set, mean and peak force and power were significantly lower in HH than NORM. At the end of the HRC training session, blood lactate and RPE in HH were significantly higher than in MH and NORM. SaO2, pH, HCO3-, and pO2 values were significantly lower in all hypoxic conditions than in NORM. CONCLUSION: These results indicate that simulated hypoxia during HRC exercise reduce blood oxygenation, pH, and HCO3-, and increased blood lactate ultimately decreasing muscular performance.

Acute Physiological and Performance Responses to High-Intensity Resistance Circuit Training in Hypoxic and Normoxic Conditions.

Ramos-Campo, DJ, Rubio-Arias, JÁ, Freitas, TT, Camacho, A, Jiménez-Diaz, JF, and Alcaraz, PE. Acute physiological and performance responses to high-intensity resistance circuit training in hypoxic and normoxic conditions. J Strength Cond Res 31(4): 1040-1047, 2017-The aim of this study was to analyze physical performance and physiological variables during high-intensity resistance circuit training (HRC) with the addition of 2 levels (moderate and high) of systemic hypoxia. Twelve resistance-trained young male subjects participated in the study. After a 6 repetition maximum testing session, participants performed 3 randomized trials of HRC: normoxia (NORM: fraction of inspired oxygen [FiO2] = 0.21; ∼0 m altitude), moderate hypoxia (MH: FiO2 = 0.16; ∼2.100 m altitude), or high hypoxia (HH: FiO2 = 0.13; ∼3.800 m altitude), as controlled by a hypoxic generator. Bench press force, heart rate and heart rate variability, rating of perceived exertion, resting metabolic rate, energy cost, and countermovement jump were assessed in each session. Heart rate variability in HH was significantly lower (standard deviation of all normal NN intervals [intervals between two "normal" beats] = 111.9 vs. 86.7 milliseconds; standard deviation of the difference between consecutive NN intervals = 19.5 vs. 17.0 milliseconds; p ≤ 0.05) in comparison with NORM. There were significant differences in rating of perceived exertion between NORM and HH (11.6 vs. 13.8 points). Peak and mean force on the bench press were significantly lower (p ≤ 0.05) in HH when compared with MH (peak: 725 vs. 488 N; mean: 574 vs. 373 N). Energy cost was significantly higher (p ≤ 0.01) in both hypoxic conditions compared with NORM (NORM: 10.4; MH: 11.7; HH: 13.3 kJ·min). There were no differences between conditions in heart rate and countermovement jump variables. These results indicate that hypoxic stimuli during HRC exercise alter physical performance and physiological variables and affect how strenuous the exercise is perceived to be. High-intensity resistance circuit training in hypoxia increases the stress on the performance and physiological responses, and these differences must be taken into account to avoid an excessive overload.

Effect of a whole-body vibration training modifying the training frequency of workouts per week in active adults.

The aim of this study was to evaluate the effects of whole-body vibration by varying the training frequency (2 or 3 sessions per week) on the development of strength, body composition, and mechanical power. Forty-one (32 men and 9 women) recreationally active subjects (21.4 ± 3.0 years old; 172.6 ± 10.9 cm; 70.9 ± 12.3 kg) took part in the study divided in 2 experimental groups (G2 = 2 sessions per week, G3 = 3 sessions per week) and a control group (CG). The frequency of vibration (50 Hz), amplitude (4 mm), time of work (60 seconds), and time of rest (60 seconds) were constant for G2 and G3 groups. Maximum isokinetic strength, body composition, and performance in vertical jumps were evaluated at the beginning and the end of the training cycle. A statistically significant increase of isokinetic strength was observed in G2 and G3 at angular velocities of 60, 180, and 270°·s. Total fat-free mass was statistically significantly increased in G2 (0.9 ± 1.0 kg) and G3 (1.5 ± 0.7 kg). In addition, statistically significant differences between G3 and CG (1.04 ± 1.7%) (p = 0.05) were found. There were no statistically significant changes in the total fat mass, fat percentage, bone mineral content, and bone mineral density in any of the groups. Both vibration training schedules produced statistically significant improvements in isokinetic strength. The vibration magnitude of the study presented an adaptation stimulus for muscle hypertrophy. The vibration training used in this study may be valid for athletes to develop both strength and hypertrophy of the lower limbs.

Sex differences in strength, functional capacity and mobility in patients with multiple sclerosis: An exploratory analysis.

BACKGROUND: Physical exercise programs are commonly designed without consideration for sex differences. Nevertheless, disease progression exhibits sex-specific patterns, resulting in different functionality and strength performances. OBJECTIVES: To analyze sex differences in strength, functional capacity, and mobility, and to evaluate sex-dependent differences in leg strength in multiple sclerosis (MS) patients. METHODS: A cross-sectional study was conducted with 35 participants (female: n = 19; Expanded Disability Status Scale (EDSS)= 3.0 ± 1.2, male: n = 16; EDSS= 3.3 ± 1.2). Body composition, maximal voluntary isometric contraction (MVIC), explosive strength (rate of force development, RFD), central activation ratio (CAR), functional capacity, and mobility were assessed. RESULTS: Differences were observed between males and females (p = 0.001) in height, lean body mass and MVIC. No differences were observed in the other variables. Regarding the leg asymmetry, men showed higher values in the stronger leg for both MVIC (p < 0.001, d=large) and RFD, whereas women showed higher values only in RFD. Men with MS demonstrated a greater capacity to produce maximal strength than women with this disease. CONCLUSIONS: The results found suggest that maximum strength differs between men and women in our sample of patients with multiple sclerosis. Furthermore, the weaker leg, regardless of sex, exhibits poorer results in explosive strength compared to the stronger leg. However, maximum strength only shows differences in men and not in women. Therefore, these findings should serve as a basis for rehabilitation professionals when planning training programs for this population.

Exercise influence on monocarboxylate transporter 1 (MCT1) and 4 (MCT4) in the skeletal muscle: A systematic review.

This review aims to systematically analyze the effect of exercise on muscle MCT protein levels and mRNA expression of their respective genes, considering exercise intensity, and duration (single-exercise session and training program) in humans and rodents, to observe whether both models offer aligned results. The review also aims to report methodological aspects that need to be improved in future studies. A systematic search was conducted in the PubMed and Web of Science databases, and the Preferred Reporting Items for Systematic review and Meta-Analyses (PRISMA) checklist was followed. After applying inclusion and exclusion criteria, 41 studies were included and evaluated using the Cochrane collaboration tool for risk of bias assessment. The main findings indicate that exercise is a powerful stimulus to increase MCT1 protein content in human muscle. MCT4 protein level increases can also be observed after a training program, although its responsiveness is lower compared to MCT1. Both transporters seem to change independently of exercise intensity, but the responses that occur with each intensity and each duration need to be better defined. The effect of exercise on muscle mRNA results is less defined, and more research is needed especially in humans. Moreover, results in rodents only agree with human results on the effect of a training program on MCT1 protein levels, indicating increases in both. Finally, we addressed important and feasible methodological aspects to improve the design of future studies.

Exploring factors of adherence to weight loss interventions in population with overweight/obesity: an umbrella review.

Adherence is key for achieving the optimal benefits from a weight loss intervention. Despite the number of studies on factors that promote adherence, their findings suggest inconsistent and fragmented evidence. The aim of this study was to review the existing factors of adherence to weight loss interventions and to find factors that facilitate the design of effective intervention programs. Six databases were searched for this umbrella review; after the screening process, 21 studies were included. A total of 47 factors were identified in six groups as relevant for adherence: (i) sociodemographic (n = 7), (ii) physical activity (n = 2), (iii) dietary (n = 8), (iv) behavioral (n = 4), (v) pharmacological (n = 3), and (vi) multi-intervention (n = 23). In addition, a map of adherence factors was created. The main findings are that with respect to demographic factors, the development of personalized intervention strategies based on the characteristics of specific populations is encouraged. Moreover, self-monitoring has been shown to be effective in behavioral, dietary, and multi-interventions, while technology has shown potential in dietary, behavioral, and multi-interventions. In addition, multi-interventions are adherence-promoting strategies, although more evidence is required on adherence to pharmacological interventions. Overall, the factor map can be controlled and modified by researchers and practitioners to improve adherence to weight loss interventions.

Effects and optimal dosage of resistance training on strength, functional capacity, balance, general health perception, and fatigue in people with multiple sclerosis: a systematic review and meta-analysis.

PURPOSE: To analyze the effectiveness of resistance training programs (RTP) on strength, functional capacity, balance, general health perception, and fatigue for people with Multiple Sclerosis (MS) and to determine the most effective dose of RTP in this population. METHODS: Studies examining the effect of RTP on strength, functional capacity, balance, general health perception, and fatigue in MS patients were included. 44 studies were included. The meta-analysis, subgroup analysis and meta-regression methods were used to calculate the mean difference and standardized mean difference. RESULTS: Significant group differences were observed in knee extensor (p = 0.01) and flexor (p < 0.001), but not in 1-repetition maximum. Regarding functional capacity and balance, differences between groups, in favour of the RTP group, were found in the Timed Up and Go Test (p = 0.001), walking endurance, (p = 0.02) gait speed (p = 0.02) and balance (p = 0.02). No significant differences between groups were observed in fatigue or general health perception. The results regarding the optimal dose are inconsistent. CONCLUSIONS: RTP improves strength, functional capacity, balance, and fatigue in people with MS. Registration: (PROSPERO): CRD42020182781Implications for rehabilitationResistance training is a valid strategy to improve isometric strength and functional capacity in MS patients.RTP using long durations (more than 6 weeks), high intensity (more than 80% 1-RM) and two-day weekly training frequency may be a correct stimulus to improve strength, functional capacity, balance, and fatigue in people with MS.Trainers and rehabilitators should consider these indicators in order to maximize muscular and functional adaptations in this population.