The effect of the ketogenic diet on resistance training load management: a repeated-measures clinical trial in trained participants.

BACKGROUND: The effect of low-carbohydrate high-fat dietary manipulation, such as the ketogenic diet (KD), on muscle strength assessment in resistance-training (RT) participants has focused on the one-repetition maximum test (1-RM). However, a pre-specified 1-RM value during an exercise training program disregards several confounding factors (i.e. sleep, diet, and training-induced fatigue) that affect the exerciser's "true" load and daily preparedness. We aimed to evaluate the effect of a 6-week RT program on load control-related variables in trained subjects following a KD intervention. METHODS: Fourteen resistance-trained individuals (3F, 11 M; 30.1 [6.2] years; 174.2 [7.6] cm; 75.7 [10.8] kg; BMI 24.8 [2.1] kg·m-2) completed this single-arm repeated-measures clinical trial. Load management variables included volume load, number of repetitions, perceived exertion (RPE), movement velocity loss, and exertion index. These primary outcomes were assessed weekly before, during, and at the end of a 6-week RT program that included traditional RT exercises (bench press, femoral lying down, lat pulldown, leg extension, and back squat). RESULTS: There was a significant difference in RPE between weeks (p = 0.015, W = 0.19) with a slight trend in decreasing RPE. We found differences in the volume load per week (p < 0.001; W = 0.73 and p < 0.001, W = 0.81, respectively), with an increase in the last weeks. In the control of the load based on movement velocity, we did not find significant differences between weeks (p = 0.591, W = 0.06), although significant differences were found in the effort index (p = 0.026, W = 0.17). CONCLUSIONS: A KD diet in recreational strength participants does not appear to lead to performance losses during a RT program aimed at improving body composition. However, the lack of adherence and familiarity with the ketogenic diet must be considered specially during first weeks.

Influence of limb dominance on body and jump asymmetries in elite female handball.

Handball is a team sport subjected to asymmetric actions that require high physical capacity demands on players. The development of large asymmetries could negatively affect sports performance. However, few studies have analyzed body composition and the force asymmetries in elite female handball players. The aim of this study was to analyze the presence of asymmetries based on limb dominance in body composition parameters and lower limb power in jumping performances in an elite women's handball team. An entire elite women's handball team, comprised by of 14 players, was analyzed. Dual X-ray Absorptiometry (DXA) and bioimpedance were used to analyze body composition. Force plates were used to evaluate jump performance. Results show the presence of differences between all the players in the different parameters of the CMJ jump. In addition, an asymmetry between the power of the dominant and non-dominant lower limb was observed between the players. The results show differences in muscle mass between the upper limbs, but not in the lower limbs in terms of both muscle and fat mass. However, there were no crossed asymmetries or significant differences between members based on dominance. The results suggest that the presence of asymmetries does not have to be one of the main parameters to be taken into account by coaches in elite athletes and to highlight the importance of including specific analyzes of body composition and sports performance in an individualized way.

Acute Effects of Blood Flow Restriction Training on Movement Velocity and Neuromuscular Signal during the Back Squat Exercise.

The aim of this study was to verify the effects of blood flow restriction on movement velocity and muscle activity during the back squat exercise. METHODS: Twenty-four university students participated in this study. In two randomized sessions 72 h apart, participants performed a 4-set protocol consisting of 30-15-15-15 repetitions performed at 30% of their one-repetition maximum in the back squat exercise. In both sessions, neuromuscular function was monitored by surface electromyography (EMG) and movement velocity (mean propulsive velocity (MPV), peak concentric velocity (Vmax), and the effort index (EI)). Blood flow restriction (BFR) was applied during exercise in one of the experimental sessions with 80% of full arterial occlusion pressure over lower limbs. RESULTS: The BFR condition showed higher (p < 0.05) EI, peak, and rooted mean square normalized EMG in Set 1 compared to Set 2. Similar MPV and Vmax were observed in each set for both the BFR and control conditions. No significant differences were observed between conditions in any set. CONCLUSIONS: BFR did not imply changes in neuromuscular performance during low-intensity resistance training, but it might induce greater intra-series velocity loss and less excitation of the muscles involved.

Efficacy of progressive versus severe energy restriction on body composition and strength in concurrent trained women.

PURPOSE: This study evaluated the concurrent training (CT) effect in combination with either progressive energy restriction (PER) or severe energy restriction (SER) on body composition and strength-related variables in resistance-trained women. METHODS: Fourteen women (29.5 ± 3.8 years; 23.8 ± 2.8 kg·m-2) were randomly assigned to a PER (n = 7) or SER (n = 7) group. Participants performed an 8-week CT program. Pre- and post-intervention measures of fat mass (FM) and fat-free mass (FFM) were assessed by dual-energy X-ray absorptiometry and strength-related variables were assessed through 1-repetition maximum (in the squat and bench press) and countermovement jump. RESULTS: Significant reductions in FM were observed in PER and SER (Δ = - 1.7 ± 0.4 kg; P = < 0.001; ES = - 0.39 and Δ = - 1.2 ± 0.6 kg; P = 0.002; ES = - 0.20, respectively). After correcting FFM for fat-free adipose tissue (FFAT), no significant differences for this variable were found either in PER (Δ = - 0.3 ± 0.1; P = 0.071; ES = - 0.06) or in SER (Δ = - 0.2 ± 0.1; P = 0.578; ES = - 0.04). There were no significant changes in the strength-related variables. No between-group differences were found in any of the variables. CONCLUSION: A PER has similar effects to a SER on body composition and strength in resistance-trained women performing a CT program. Given that PER is more flexible and thus may enhance dietary adherence, it might be a better alternative for FM reduction compared to SER.

Is the Relationship between Acute and Chronic Workload a Valid Predictive Injury Tool? A Bayesian Analysis.

This study aimed to evaluate the relationship between injury risk, acute load (AL), acute chronic workload ratio (ACWR) and a new proposed ACWR. DESIGN: a retrospective cohort study of the year 2018 was conducted on Argentine first-division soccer players. PARTICIPANTS: Data from 35 players (age = 26.7 ± 4.71 years; height = 176.28 ± 6.09 cm; mass = 74.2 ± 5.27 kg) were recorded; 12 players' data were analyzed for 1 year, and 23 players' data were analyzed for 6 months. INTERVENTIONS: The mean difference of ACWR (MD = 0.22), high-density interval (HDI 95% = (0.07, 0.36)) and AL (MD = 449.23, HDI 95% = (146.41, 751.2)) between groups turned out to be statistically significant. The effect size between groups comparing ACWR and AL was identical (ES = 0.64). RESULTS: The probability of suffering an injury conditioned by ACWR or random ACWR was similar for all estimated quantiles, and the differences between them were not statistically significant. CONCLUSIONS: The ACWR ratio, using internal load monitoring, is no better than a synthetic ACWR created from a random denominator to predict the probability of injury. ACWR should not be used in isolation to analyze the causality between load and injury.

Associations between Muscle Strength, Physical Performance and Cognitive Impairment with Fear of Falling among Older Adults Aged ≥ 60 Years: A Cross-Sectional Study.

(1) Background: Fear of falling has become a significant health problem in older adults and is already considered as important as falling because of its long-term detrimental effects on older adults' physical and psychosocial functioning. The aim of this study was to analyze the associations between both upper and lower limb strength, gait parameters and cognitive impairment with fear of falling in older adults. (2) Methods: A cross-sectional study involving 115 older-adult participants was used to assess the impact of both upper (Handgrip dynamometer, TKK 5401 Grip-D, Takey, Tokyo, Japan) and lower limb strength (Chair stand test), gait parameters (OptoGait-System Bolzano, Bolzano, Italy) and cognitive impairment (COWAT word association test) with fear of falling in older adults (Falls Efficacy Scale-International FES-I). (3) Results: Multivariate linear regression analysis showed several independent associations with the fear of falling. A higher time to perform the Chair Stand test was associated with higher scores in FES-I (R2 = 0.231), while a lower score in both Semantic Fluency (S COWA) and Phonologic Fluency (P COWA) was associated with a decreased score in FES-I (R2 = 0.052 and 0.035). (4) Conclusions: Both higher step and stride length (OptoGait), lower body strength (Chair test) and both poorer semantic (S COWA) and phonologic (P COWA) fluency were all associated with fear of falling.

Effects of Preceding Transcranial Direct Current Stimulation on Movement Velocity and EMG Signal during the Back Squat Exercise.

This study aimed to evaluate the effects of preceding anodal transcranial direct stimulation (a-tDCS) over the dorsolateral prefrontal cortex (DLPFC) during the back squat exercise on movement velocity and surface electromyographic (sEMG) activity. Thirteen healthy, well-trained, male firefighters (34.72 ± 3.33 years; 178 ± 7.61 cm; 76.85 ± 11.21 kg; 26.8 ± 4.2 kg·m−2; back squat 1-repetition maximum 141.5 ± 16.3 kg) completed this randomised double-blinded sham-controlled crossover study. After familiarisation and basal measurements, participants attended the laboratory on two occasions separated by 72 h to receive either Sham or a-tDCS (current intensity of 2 mA for 20 min). Immediately after stimulation, participants completed three sets of 12 repetitions (70% of 1-RM) with three minutes of recovery between sets monitored with a linear position transducer. The sEMG of the rectus femoris (RF) and vastus lateralis (VL) of both legs were recorded. No significant differences were observed between a-tDCS and Sham interventions on mean concentric velocity at any set (p > 0.05). Velocity loss and effort index were significantly higher (p < 0.05) in set 3 compared to set 1 only in the a-tDCS group. The right-leg RM and right-leg VL elicited the greatest muscle activation during set 1 after a-tDCS and Sham, respectively (p < 0.05). Our results revealed that a-tDCS over the DLPFC might impact movement velocity or fatigue tolerance in well-trained individuals. Notwithstanding, significant differences in dominant-leg muscle activity were found both in a-tDCS and Sham.

A randomized open-labeled study to examine the effects of creatine monohydrate and combined training on jump and scoring performance in young basketball players.

Background: Creatine monohydrate (CrM) supplementation has been shown to be an effective and safe nutritional supplement to improve performance; however, the impact of CrM supplementation in young basketball players is less clear. This study evaluated the effects of CrM supplementation during a strength and conditioning training (SCT) program on lower-limb strength parameters and performance in under-16 (U16) basketball players. Methods: Twenty-three male U16 basketball players participated in this study (14.3 ± 0.4 years; BMI: 20.7 ± 2.2 kg∙m-2). The players were randomly assigned to either a CrM group (n = 12) that ingested 0.1 g·kg-1·day-1 of CrM or to a non-supplemented control group (n = 11, CON). The athletes participated in an 8-week SCT program consisting of two lower-limb resistance-training sessions and two plyometric sessions per week. Squat jump (SJ), drop jump (DP), countermovement jump (CMJ), and Abalakov (ABK) jump power tests as well as basketball performance (points and minutes per game) were measured before, during and/or after the intervention. Data were analyzed using a general linear model with repeated measures with independent Student's t-test pairwise comparisons. Results: The results (95% confidence interval for mean change from baseline) show that there were significant differences for all variables for CrM and CON, respectively: SJ (cm): 2.6 - 6.4, P < 0.01 and 2.2-5.1 P < 0.01; DJ (cm): 2.5-5.6, P < 0.01, and 1.8-4.4, P < 0.01; CMJ (cm): 0.3-0.8, P < 0.01, and 0.2-0.5, P < 0.01; ABK (cm): 2.8-5.5, P < 0.01 and 0.7-2.6, P = 0.003. A significant group x time interaction (p = 0.003, ηp 2 = 0.342) was observed in ABK performance. No significant group x time effects were seen in squat jump (p = 0.449, ηp 2 = 0.028), drop jump (p = 0.143, ηp 2 = 0.099), or counter movement jump (p = 0.304, ηp 2 = 0.05). A significant interaction effect was also observed in points per game (p = 0.049, ηp 2 = 0.149), while a non-significant but medium effect was seen in minutes per game (p = 0.166, ηp 2 = 0.094). Conclusions: CrM supplementation in conjunction with resistance and plyometric training increased the lower-limb ABK power and scoring performance in U16 basketball players.

Traditional and Undulating Periodization on Body Composition, Strength Levels and Physical Fitness in Older Adults.

INTRODUCTION: Undulating training has been investigated in sedentary and trained adults, but less is known about the influence of undulating training in older adults. PURPOSE: This study aimed to evaluate body composition, strength levels, and physical fitness in response to traditional or undulating training in older adults. METHODS: A controlled, double-arm trial was conducted in eighteen older adults (10 males, 8 females; 64 ± 2.1 years; 165.12 ± 7.5 cm; 72.5 ± 11.4 kg; 26.5 ± 3.2 k·gm-2) who were randomly assigned to traditional (n = 9, TT) or undulating training (n = 9, UT) for eight weeks. Dual X-ray absorptiometry was used to measure fat-free mass (FFM), fat mass (FM), and bone mineral density (BMD). Strength levels were evaluated by the handgrip strength and the one-repetition maximum in vertical chest press, rowing machine, squat, monopodal horizontal leg press, and leg extension. In addition, functional capacity was assessed using the Senior Fitness Test (SFT). Statistical analysis included mean/median comparisons to establish the difference after the intervention (paired Student's t-test or Wilcoxon test), and effect size calculations based on estimates. RESULTS: After correction for fat-free adipose tissue, a significant increase in FFM was observed in both groups, while no significant changes were found in FM and BMD. Upper- and lower-limbs strength showed significant increases in both groups, although clinical significance varied among exercises. Favorable results were seen on the cardiorespiratory fitness and strength components of the SFT in both groups. CONCLUSIONS: The 8-week UT and TT protocols are valid options for improving FFM and increasing strength and functional capacity in women and men over 60 years of age.

Handgrip Strength-Related Factors in a Colombian Hypertensive Population: A Cross-Sectional Study.

(1) Background: This study determined the factors associated with manual grip strength in people with high blood pressure (HBP); (2) Methods: 219 subjects participated in this cross-sectional study, which evaluated muscle strength (manual dynamometer), sociodemographic factors, clinical characteristics, level of physical activity (International Physical Activity Questionnaire-IPAQ score), and depression (Zung's Depression Self-Rating Scale); (3) Results: The bivariate analysis found that handgrip strength in people with HPB was associated with sex (p = 0.000), age (p = 0.000), ethnicity (p = 0.019), smoking habits (p = 0.037), alcohol consumption (p = 0.004), diastolic blood pressure (p = 0.012), weight (p = 0.000), height (p = 0.000), measurement of waist circumference (p = 0.002), depression (p = 0.041), and IPAQ score (p = 0.000). Regardless of being male or female, handgrip strength was associated with age (p = 0.009), IPAQ (p = 0.000), weight (p = 0.038), height (p = 0.000), DPB units (p = 0.043), and depression (p = 0.020). The multivariate generalized linear gamma regression model showed that the coefficient with the greatest weight, regardless of sex, was age (p = 0.043), level of physical activity (24% more at high level than at low level, p = 0.031), and depression (moderate/severe depression level) associated with lower handgrip strength (p = 0.025); (4) Conclusions: Handgrip strength showed an association with level of physical activity, age, and level of depression in a middle-aged population with HBP.

Acute Effects of a Percussive Massage Treatment on Movement Velocity during Resistance Training.

The aim of this research was to verify whether the application of percussion therapy during inter-set rest periods increases the number of repetitions performed before reaching a 30% velocity loss threshold during a bench press exercise. Methods: Twenty-four male university students participated in this study (24.3 ± 1.3 years; 77.5 ± 8.3 kg; 177.0 ± 5.6 cm; 24.7 ± 2.6 kg∙m-2). Participants were randomized into two groups: a percussion therapy group (PTG) and a control group (CG). They performed 4 sets at 70% of a one-repetition maximum before reaching a 30% velocity loss threshold with an inter-set recovery of 3 min. Results: The PTG performed a greater total number of repetitions compared to the CG (44.6 ± 4.8 vs. 39.5 ± 6.8; p = 0.047; ES = 0.867). No differences were observed for the different movement velocity variables and fatigue control (p > 0.05). Conclusions: Percussion therapy is an effective method to delay the loss of movement velocity in the bench press exercise.

Creatine Enhances the Effects of Cluster-Set Resistance Training on Lower-Limb Body Composition and Strength in Resistance-Trained Men: A Pilot Study.

Creatine monohydrate (CrM) supplementation has been shown to improve body composition and muscle strength when combined with resistance training (RT); however, no study has evaluated the combination of this nutritional strategy with cluster-set resistance training (CS-RT). The purpose of this pilot study was to evaluate the effects of CrM supplementation during a high-protein diet and a CS-RT program on lower-limb fat-free mass (LL-FFM) and muscular strength. Twenty-three resistance-trained men (>2 years of training experience, 26.6 ± 8.1 years, 176.3 ± 6.8 cm, 75.6 ± 8.9 kg) participated in this study. Subjects were randomly allocated to a CS-RT+CrM (n = 8), a CS-RT (n = 8), or a control group (n = 7). The CS-RT+CrM group followed a CrM supplementation protocol with 0.1 g·kg-1·day-1 over eight weeks. Two sessions per week of lower-limb CS-RT were performed. LL-FFM corrected for fat-free adipose tissue (dual-energy X-ray absorptiometry) and muscle strength (back squat 1 repetition maximum (SQ-1RM) and countermovement jump (CMJ)) were measured pre- and post-intervention. Significant improvements were found in whole-body fat mass, fat percentage, LL-fat mass, LL-FFM, and SQ-1RM in the CS-RT+CrM and CS-RT groups; however, larger effect sizes were obtained in the CS-RT+CrM group regarding whole body FFM (0.64 versus 0.16), lower-limb FFM (0.62 versus 0.18), and SQ-1RM (1.23 versus 0.75) when compared to the CS-RT group. CMJ showed a significant improvement in the CS-RT+CrM group with no significant changes in CS-RT or control groups. No significant differences were found between groups. Eight weeks of CrM supplementation plus a high-protein diet during a CS-RT program has a higher clinical meaningfulness on lower-limb body composition and strength-related variables in trained males than CS-RT alone. Further research might study the potential health and therapeutic effects of this nutrition and exercise strategy.

Comparison of Interventional Strategies to Improve Recovery after Eccentric Exercise-Induced Muscle Fatigue.

The aim of this study was to compare the effects of various recovery techniques on muscle tissue after eccentric exercise-induced muscle fatigue (EIMF). Forty subjects (24.3 ± 2.6 years; 77.45 ± 8.3 kg; 177.0 ± 6.4 cm; 24.66 ± 1.6 kg∙m-2) were randomly assigned to one of the following groups: manual therapy (n =10, MT), mechanical vibration (n = 10, MV), percussion therapy (n = 10, PT) or foam roller (n = 10, FR). The contraction time (Tc) and the radial displacement (Dm) of the gastrocnemius was evaluated through tensiomyography (TMG). The application of the different techniques had positive effects for Tc and Dm in the treated leg compared to the untreated leg (F = 50.01, p < 0.01, η2p = 0.58 and F = 27.58, p < 0.01, η2p = 0.43, respectively) and for the interaction of the factors (Time x Leg x Therapy: F = 5.76, p < 0.01, η2p = 0.32 and F = 5.93, p < 0.01, η2p = 0.33, respectively). The results of the various methods used were similar: Tc (F = 0.17, p = 0.917; η2p = 0.01) and Dm (F = 3.30, p = 0.031, η2p = 0.22). PT interventions show potential for restoring muscle compliance and reducing stiffness, similar to MT and possibly more effective (cost-time relationship) compared to MV or FR.

¿Es efectivo el entrenamiento sobre superficies inestables para jugadores de golf de alto nivel? / Is training on unstable surfaces for high level golf players effective?

El propósito de esta investigación, fue estudiar la eficiencia del entrenamiento de estabilidad lumbopélvica, realizado en superficies estables e inestables, y cómo este afecta a la velocidad y distancia de golpeo en golf, en jugadores de alto rendimiento. OBJETIVO: Comprobar si es realmente eficaz entrenar sobre superficies inestables para un golfista de élite. CONFIGURACIÓN Y DISEÑO: Cuasi experimental, de pre y post tratamiento de un grupo. MATERIAL Y MÉTODOS: Participaron en el estudio veinticinco varones y 2 mujeres (24 ± 5,3 años; 181 ± 4 cm, 76,8 ± 6,35 kg), fueron aleatorizados a los grupos de entrenamiento en superficie estable (GE, n=14) o entrenamiento en superficie inestable (GI, n=13). Se realizaron mediciones de distancia y velocidad con Trackman golf®, ejecutando cada sujeto cinco golpeos obteniendo la media y la mejor de las distancias. Estas mediciones se realizaron pre y post intervención. Se utilizaron como unidades de medida, metros (m) para la distancia y millas por hora para velocidad de golpeo (mph). ANÁLISIS ESTADÍSTICO UTILIZADO: Prueba t-Student de muestras emparejadas. RESULTADOS: Se realizó una prueba t-Student de los valores medios ambos grupos de golpeo pre y post entrenamiento. Encontramos tendencias que nos indican, que, efectivamente, entrenar sobre superficies inestables no es eficiente para el golfista de alto nivel. Se encontraron diferencias significativas en distancia Carry (CD) pre y post test del GE de 225,1m a 232,9m (p < 0,027) y mejoras no significativas en velocidad de la cabeza del palo (CHS) pre y post test de 105,8 mph a 107,1 mph (p > 0,05). Mientras que el GI, no mostró resultados significativos en ninguno de los parámetros, CD mejoró de 223,3m a 225,4m (p > 0,05) y CHS disminuyó de 104,4 mph a 103,4 mph. CONCLUSIONES: Con los datos obtenidos, podemos concluir que el entrenamiento sobre superficies inestables, a pesar de ser norma común en el golf de élite, no parece mejorar el rendimiento de una acción tan determinante en el juego como es el swing

The purpose of this research was to study the efficiency of the lumbar-pelvic stability training, carried out on stable and unstable surfaces, and how this affects the speed and hitting distance in golf, in high performance players. AIM: See if training on unstable surfaces is really effective for an elite golfer. SETTINGS AND DESIGN: Quasi experimental, pre and post treatment of a group. MATERIAL AND METHODS: Twenty-five males and 2 females (24 ± 5.3 years; 181 ± 4 cm, 76.8 ± 6.35 kg) participated in the study, were randomized to the training groups on stable surface (GE, n = 14) or training on unstable surface (GI, n = 13). Distance and speed measurements were made with Trackman golf®, each subject executing five blows obtaining the mean and the best of the distances. These measurements were made pre and post intervention. Meters for distance and miles per hour for hitting speed (mph) were used as units of measurement. STATISTICAL ANALYSIS USED: Student t-test of paired samples. RESULTS: A t-Student test of the mean values ​​of both groups of pre and post training hitting was performed. We find trends that indicate that, indeed, training on unstable surfaces is not efficient for the high-level golfer. Significant differences were found in the Carry distance (CD) pre and post test of the GE from 225.1m to 232.9m (p <0.027) and non significant improvements in club head speed (CHS) pre and post test of 105, 8 mph to 107.1 mph (p> 0.05). While the GI did not show significant results in any of the parameters, CD improved from 223.3m to 225.4m (p> 0.05) and CHS decreased from 104.4mph to 103.4mph. CONCLUSIONS: With the data obtained, we can conclude that training on unstable surfaces, despite being a common norm in elite golf, does not seem to improve the performance of an action as decisive in the game as swing