Postactivation performance enhancement in the vertical jump using loads above or below the optimum-power load for a jump squat.

BACKGROUND: Postactivation performance enhancement (PAPE) is an acute response of increased muscle performance following a conditioning activity (CA), generally prescribed based on the percentage of a one-repetition maximum. However, it is unknown how the PAPE response is affected when the CA is performed near the optimum power zone. The purpose of this study was to examine PAPE using loads that were 20% above or below the optimum-power load (OPL). METHODS: Fifteen recreationally trained subjects, with at least one-year resistance training experience participated in this study. First, the OPL for the JS was determined. Then, subjects performed two protocols in a counterbalanced order: 20% above (+20%OPL) or below (-20%OPL). To examine PAPE on performance, the vertical jump was performed prior to and seven times following each jump squat protocol, with a 2-min rest interval between trials. RESULTS: The two-way ANOVA revealed main effects for condition (F=4.978; P<0.001) for jump height and jump power (F=2.589; P=0.017), but post-hoc comparisons did not show differences. Between baseline and the best trial following each jump squat protocol, two-way ANOVA did not reveal main effects (F=3.048; P=0.103) or interactions (F=0.304; P=0.590). Paired t-tests did not show significant differences between conditions for relative changes in jump height (P=0.543) or jump power (P=0.233). CONCLUSIONS: This study revealed similar results between 20% above or below the OPL on subsequent vertical jump performance.

Effect of Static Stretching on Agonists, Antagonists, and Agonist-Antagonist Combination on Total Training Volume.

The purpose of this study was to examine the effects of static stretching (SS) of agonists and antagonists between sets on the total training volume (TTV) performed across multiple sets for the leg extension exercise. Twelve male subjects with experience in resistance training (RT) participated in this study. Subjects performed 10 repetition maximum (10RM) test and retest trials for the leg extension exercise. Four different protocols were randomly applied as follows: quadriceps stretching (AG); hamstrings stretching (AN); quadriceps and hamstrings stretching (AGN); and traditional control without stretching (TR). Significant differences (p≤0.05) were observed in the TTV between the AG (4855.42 ± 1279.38 kg) and AN (6002.08 ± 1805.18 kg), AGN (5977.50 ± 1778.49 kg), and TR (6206.04 ± 1796.15 kg) protocols. These results suggest that when practicing inter-set SS, it should be done for antagonist rather than agonist muscles when the intent is to maximize TTV.

Effects of Different Recovery Modalities on Delayed Onset Muscle Soreness, Recovery Perceptions, and Performance Following a Bout of High-Intensity Functional Training.

The purpose of this study was to investigate the effects of the foam rolling technique and static stretching on perceptual and neuromuscular parameters following a bout of high-intensity functional training (HIFT), which consisted of 100 pull-ups, 100 push-ups, 100 sit-ups, and 100 air squats (Angie benchmark) in recreationally trained men (n = 39). Following baseline measurements (Feeling Scale, Visual Analogue Scale, Total Quality Recovery, Sit-and-Reach, Countermovement Jump, and Change-of-Direction t-test), the volunteers performed a single bout of HIFT. At the end of the session, participants were randomly assigned to one of three distinct groups: control (CONT), foam rolling (FR), or static stretching (SS). At the 24 h time-point, a second experimental session was conducted to obtain the post-test values. The level of significance was set at p < 0.05. Regarding power performance, none of the three groups reached pretest levels at 24 h point of the intervention. However, the CONT group still showed a greater magnitude of effect at the 24 h time-point (ES = 0.51, p ≥ 0.05). Flexibility presented the same recovery pattern as power performance (post × 24 h CONT = ES = 0.28, FR = ES = 0.21, SS = ES = 0.19). At 24 h, all groups presented an impaired performance in the COD t-test (CONT = ES = 0.24, FR = ES = 0.65, SS = ES = 0.56 p ≥ 0.05). The FR protocol resulted in superior recovery perceptions (pre × 24 h TQR = ES = 0.32 p ≥ 0.05). The results of the present study indicate that the use of FR and SS exercises may not be indicated when aiming to restore neuromuscular performance following a single bout of HIFT. The use of the FR technique during the cooldown phase of a HIFT session may be helpful in improving an individual's perception of recovery.

Are Self-Selected Intervals as Effective as Fixed Intervals in Controlling Acute Responses in High-Intensity Interval Resistance Training?

Physical conditioning programs often apply high-intensity resistance training (HIRT), but there is a lack of research investigating the effects of using fixed or self-selected resting intervals between exercises on the performance, relative intensity, and affective perception during this modality of training. This study compared fixed versus self-selected rest intervals in HIRT sessions on cardiorespiratory responses, number of repetitions, and enjoyment perception in trained young men. Sixteen trained males (27.1 ± 3.9 years; 56.6 ± 7.5 mL.kg-1.min-1) performed HIRT circuits with 30-s and self-selected recovery interval. The duration of resting intervals was longer in HIRT performed with fixed than self-selected intervals (14.04 ± 5.82 s; p < 0.0001; ES = 3.2). Both sessions elicited similar relative HRR (79.4 ± 6.2 % vs. 81.6 ± 4.2 %; p = 0.14), VO2R (43.0 ± 12.2% vs. 47.7 ± 9.6%; p = 0.10), and enjoyment reflected by scores in the PACES questionnaire (107.9 ± 15.1 vs. 109.2 ± 12.8; p = 0.65). The total number of repetitions (403.4 ± 45.5 vs. 353.1 ± 27.4; p < 0.01, ES = 1.3) and caloric expenditure (154.4 ± 28.6 kcal vs. 121.4 ± 21.6 kcal; p < 0.001, ES = 0.13) were greater in HIRT performed with fixed vs. self-selected intervals. In conclusion, HIRT performed with fixed and self-selected rest intervals elicited similar relative intensity and enjoyment perception. However, the number of repetitions and caloric expenditure were greater in sessions performed with fixed 30-s.

Effects of Differing Foam Rolling Periods on Training Volume and Myoelectric Responses of Lower-Body Muscles.

ABSTRACT: Santana, HG, Paz, GA, Willardson, JM, de Araújo Farias, D, and Miranda, H. Effects of differing foam rolling periods on training volume and myoelectric responses of lower-body muscles. J Strength Cond Res 36(12): 3311-3318, 2022-Foam rolling (FR) is a practice that has increased in popularity before and after resistance training. The purpose of this study was to compare the acute effects of different foam rolling periods for the lower body muscles on subsequent performance, myoelectric activity and rating of perceived exertion in trained men. Fourteen men (26.2 ± 3.2 years, 178 ± 0.04 cm, 82.2 ± 10 kg and body mass index 25.9 ± 3.3kg/m -2 ) volunteered for this study. Four repetition maximum (4-RM) loads were determined for hexagonal bar deadlift and 45°-angled leg press during test and retest sessions over two nonconsecutive days. The experimental conditions included a traditional protocol (TP) with no prior foam rolling, and four other conditions that involved FR applied to the quadriceps, hamstrings and triceps surae for one set of 30 sec (P1), two sets of 30 sec (P2), three sets of 30 sec (P3), or four sets of 30 sec (P4).The resistance training consisted of five sets with 4-RM loads. The number of repetitions completed, the myoelectric activity of lower limbs were recorded, as well as the rating of perceived exertion for each protocol. There were no differences between the protocols in the total repetitions for the hexagonal bar deadlift and 45° angled leg press exercises. Similar results between protocols were also noted for muscle activity and rated perceived exertion (RPE). Therefore, the results of the present study indicated that the FR didn't provide effects on performance, myoelectric activity and rating of perceived exertion responses during high intensity resistance performance for lower limb exercises.

Correlation between lower limb and trunk muscle endurance with drop vertical jump in the special military forces.

OBJECTIVE: Police officers, particularly the ones who are trained to be on "special forces", perform a wide range of hazardous and physically demanding activities when aiming to protect and serve. The purpose of this study was to investigate the association between lower limb and trunk muscle endurance with drop vertical jump (DVJ) height in a special military police force. METHODS: One hundred and three male military men (age: 36 ± 5.0 years; height: 1.76 ± 0.05 m; weight: 81.8 ± 9.7 kg) volunteered to take part in this study. SIX TESTS WERE PERFORMED: DVJ, McGill core battery (trunk flexion, trunk extension, and side bridge test-right and left), and single-leg squat repetitions. Correlations were analyzed using the Pearson correlation coefficient (r). The level of significance for all analyses was set at p ≤ 0.05. RESULTS: Single-leg squat repetitions were positively associated with DVJ height, contact time and flight time (p = 0.00093∗∗, p = 0.00085∗∗, and p = 0.00098∗∗ respectively). No correlation was observed between trunk muscle endurance and DVJ. CONCLUSION: Therefore, it was concluded that greater endurance of the lower limb muscles, as demonstrated by the single leg squat, was associated with better performance in a DVJ. Individuals should consider incorporating single leg squats into their fitness program to develop muscular endurance and possibly perform better in the DVJ.

Effect of Different Numbers of Interset Antagonist Proprioceptive Neuromuscular Facilitation Stretching on the Total Number of Repetitions for the Agonists.

Recent studies have observed that stretching applied to antagonist muscles can promote improvement in agonist muscle performance. The purpose of this study was to investigate the effect of different numbers of interset proprioceptive neuromuscular facilitation (PNF) stretching for the antagonists on the total number of repetitions completed for the agonists (quadriceps) in the leg extension exercise. Fourteen physically active individuals (age: 29.35 ± 10.5 years; body mass: 79.1 ± 11.34 kg; height: 170.4 ± 8.7 cm) participated in this study. The following experimental protocols were performed: 1) Traditional protocol (Traditional) - without previous stretching; 2) PNF with lesser duration (PNF1-3 sets of 20 secs.); 3) PNF with greater duration (PNF2-3 sets of 30 secs.). Within the experimental protocols (PNF1 and PNF2), stretching exercises for the antagonists were performed before and between the four sets of the unilateral leg extension exercise. All tests were performed on the dominant limb only. The results showed that there was a significant difference in the total number of repetitions for the PNF2 protocol versus the Traditional protocol (p = 0.026). However, there was no significant difference between the PNF1 protocol versus the Traditional protocol (p = 0.577). In conclusion, in the leg extension exercise, an extended duration of interset PNF stretching for the hamstrings, promoted greater contractile performance for the quadriceps as demonstrated by significantly greater total repetitions over four sets.

Association between handgrip strength and body composition, physical fitness, and biomarkers in postmenopausal women with metabolic syndrome.

OBJECTIVES: This study examined the association between handgrip strength and body composition, physical fitness, and biomarkers in postmenopausal women with metabolic syndrome. METHODS: A total of 75 postmenopausal women were diagnosed with metabolic syndrome participated in this study. Muscle strength was assessed via a hydraulic grip strength dynamometer; physical fitness tests included a timed-up-and-go, arm curl test, and 30-s chair stand. Body composition was assessed via bioelectrical impedance, from which estimates of fat mass, body fat percentage, fat-free mass, and visceral fat area were determined. Fasting plasma glucose and glycated hemoglobin were measured via blood sample analyses. Multiple linear regression analyses were conducted using handgrip strength as the dependent variable and using body composition, physical fitness, and biomarkers as independent variables. RESULTS: The results revealed that 52% of the total sample were classified as obese, 37.3% as overweight, and only 10.7% as normal weight. Significant correlations were present between handgrip strength and fat-free mass (p=0.002; R=0.590), mean blood pressure (p=0.002; R=0.450), and arm curl (p=0.001; R=0.795). CONCLUSION: This study showed that handgrip strength was predictive of fat-free mass, blood pressure, and upper limb strength performance.

Association between handgrip strength and body composition, physical fitness, and biomarkers in postmenopausal women with metabolic syndrome

SUMMARY OBJECTIVES: This study examined the association between handgrip strength and body composition, physical fitness, and biomarkers in postmenopausal women with metabolic syndrome. METHODS: A total of 75 postmenopausal women were diagnosed with metabolic syndrome participated in this study. Muscle strength was assessed via a hydraulic grip strength dynamometer; physical fitness tests included a timed-up-and-go, arm curl test, and 30-s chair stand. Body composition was assessed via bioelectrical impedance, from which estimates of fat mass, body fat percentage, fat-free mass, and visceral fat area were determined. Fasting plasma glucose and glycated hemoglobin were measured via blood sample analyses. Multiple linear regression analyses were conducted using handgrip strength as the dependent variable and using body composition, physical fitness, and biomarkers as independent variables. RESULTS: The results revealed that 52% of the total sample were classified as obese, 37.3% as overweight, and only 10.7% as normal weight. Significant correlations were present between handgrip strength and fat-free mass (p=0.002; R=0.590), mean blood pressure (p=0.002; R=0.450), and arm curl (p=0.001; R=0.795). CONCLUSION: This study showed that handgrip strength was predictive of fat-free mass, blood pressure, and upper limb strength performance.

Association Between Upper Limb Strength Through 1-Repetition Maximum Test and V'O2peak in Heart Failure.

Purpose: This study aimed to evaluate whether there is a correlation between the maximum strength of upper limb when performing a multijoint exercise and peak oxygen uptake (V'O2peak) in Chronic Heart Failure (CHF) subjects. Method: This cross-sectional study involved CHF subjects with a left ventricular ejection fraction (LVEF) less than 50%, who underwent a cardiopulmonary exercise test (CPET) on a treadmill and 1-repetition maximum (1-RM) test for upper limb strength using a bench press exercise. Results: The sample consisted of 16 individuals aged 54 ± 12 years with a LVEF of 37 ± 7%. The V'O2peak was 14.98 ± 5.4 ml·min-1·kg-1 and mean maximum load in the 1-RM test was 38 ± 16 kg. There was strong correlation of V'O2peak with the load in the 1-RM test (r = 0.70; p = .037; r2 = 0.48). Conclusion: There is a strong correlation between the load in 1-RM test for upper limb with V'O2peak in CHF individuals. It is a safe, inexpensive and reproducible way to assess the muscle strength in this population.

The Effect of Different Rest Intervals Between Agonist-Antagonist Paired Sets on Training Performance and Efficiency.

ABSTRACT: Behenck, C, Sant'Ana, H, Pinto de Castro, JB, Willardson, JM, and Miranda, H. The effect of different rest intervals between agonist-antagonist paired sets on training performance and efficiency. J Strength Cond Res 36(3): 781-786, 2022-The purpose of this study was to verify the effect of different rest intervals (RIs) between agonist-antagonist paired sets (APS) on training performance and efficiency. Eighteen recreationally trained men (age: 21.5 ± 2.1 years, body mass: 74.5 ± 10.4 kg, height: 1.75 ± 0.04 m, body mass index: 24.4 ± 3.7 kg·m-2) completed 4 sessions. During each session, a 10-repetition maximum load was used for 3 APS of Bench Row + Bench Press and Lat Pull-down + Overhead Press with RI between APS sequences of 1, 2, 3 minutes (min) or self-selected RI (SRI). Total training volume (TTV), session time and efficiency were measured in all sessions. The 1-minute RI resulted in significantly less TTV vs. the other conditions (p = 0.000). The 2-minute RI resulted in significantly less TTV vs. the 3-minute RI (p = 0.002), but the SRI was not significantly different vs. the 3-minute RI. For session time, the 1-minute RI was significantly less (p = 0.000) and the 3-minute RI was significantly greater (1-minute and 2-minute RI, p = 0.000; SRI, p = 0.010) than the other conditions. Therefore, the efficiency of the 1-minute RI was significantly greater vs. the other conditions (3-minute RI and SRI, p = 0.000; 2-minute RI, p = 0.001) and the 2-minute RI was significantly greater vs. the 3-minute RI (p = 0.001). There were no significant differences in TTV, session time, and efficiency between the 2-minute RI and SRI conditions. In conclusion, the 2-minute RI and SRI conditions may present a better cost-effectiveness. It is suggested that self-selected RI can provide better performance, whereas 2-minute RI may enable greater efficiency.

Postural control in football players with vision impairment: Effect of sports adaptation or visual input restriction?

Abstract Aim: To assess the postural control performance of football 5-a-side (FFS) players, comparing them with sighted players. Methods: Eight FFS players and 7 sighted futsal players were included. Postural control tests included feet together stance (FTS) and single-leg stance (SLS) tasks, performed on rigid and foam surfaces. Sighted players performed the tests with open (EO) and closed (EC) eyes. Area of displacement (Area) and average velocity (Vavg) were calculated from the center of pressure time-series coordinates. Results: On both surfaces conditions, a significant difference between visually impaired football 5-a-side players and sighted EO players was observed during FTS (higher Vavg for visually impaired football 5-a-side players; p < 0.04) and SLS (higher Area and Vavg for visually impaired football 5-a-side players; p < 0.01). No differences between visually impaired football 5-a-side players and sighted EC players were found. Differences between sighted EO vs. sighted EC were observed during FTS on the foam surface, and in SLS on both surface conditions (p < 0.03). Conclusion: FFS players' postural control performance is similar to sighted players with EC but worse than sighted players with EO, suggesting their postural control performance can be simply explained in terms of visual restriction.

The effect of self myofascial release and static stretching on the antagonist muscles before agonist performance / Efecto de la autoliberación miofascial y el estiramiento estático previos de la musculatura antagonista en el rendimento de la musculatura agonista / Efeito da auto-liberação miofascial e alongamento estático no músculo antagonista antes do desempenho agonista

Objective: The aim of this study was to compare differences in volume load, total repetition performed and rating of perceived exertion between static stretching and self-myofascial release on antagonist muscles.Methods: Eighteen recreationally trained men (23.4 ± 3.3 years; 80.7 ± 11.1 kg; 1.76 ± 0.06 cm) performed 10 repetitions maximum test and retest in the leg extension exercise on the first two visits. Then, three experimental sessions were conducted in a random order, in which two consisted of self-myofascial release and static stretching on hamstrings, and the other was used as a control.Results: Significant higher repetitions were performed in the third set of static stretching when compared to control protocol. Additionally, significant reductions in total repetitions performed were observed only in the control session. No significant differences were noticed in the volume load of leg extension and rating of perceived exertion between protocols.Conclusion: Self-myofascial release and static stretching performed before a session in the antagonist muscles can maintain repetitions performance by optimizing recovery between sets and reducing fatigue of agonist muscle. (AU)

Objetivo: El objetivo de este estudio fue comparar las diferencias entre el volumen de la carga, el número total de repeticiones y la percepción subjetiva del esfuerzo, de la musculatura agonista, tras estiramiento estático y liberación miofascial de los músculos antagonistas.Método: Dieciocho hombres entrenados recreativamente (23.4 ± 3.3 años; 80.7 ± 11.1 kg; 1.76 ± 0.06 cm) realizaron un test retest de 10 repeticiones máximas de extensión de rodilla en las dos primeras visitas. A continuación, se llevaron a cabo tres series en orden aleatorio que consistieron dos en autoliberación miofascial y estiramiento estático de los isquiosurales, y la otra se usó como control.Resultados: En la tercera serie se obtuvo un mayor número de repeticiones tras estiramientos estáticos en comparación con el control. Además, se encontraron reducciones significativas en las repeticiones solo en la serie control. Entre los protocolos, no hubo diferencias en el volumen de rendimiento y la percepción subjetiva del esfuerzo.Conclusión: La liberación miofascial y el estiramiento estático de los músculos antagonistas, realizados antes de la sesión pueden mantener el rendimento en repeticiones a lo largo de las series, al optimizar la recuperación entre series y reducir la fatiga del músculo agonista. (AU)

Objetivo: O objetivo deste estudo foi comparar diferenças no volume de treinamento, repetições totais e percepção subjetiva de esforço entre alongamento estático e auto-liberação miofascial nos músculos antagonistas.Método: Dezoito homens recreacionalmente treinados (23.4 ± 3.3 anos; 80.7 ± 11,1 kg; 1.76 ± 0.06 cm) realizaram teste e reteste de 10 repetições máximas na cadeira extensora nas primeiras duas visitas. Em seguida, foram realizadas três sessões de ordem aleatória, onde duas consistiram de auto-liberação miofascial e alongamento estático, e outra foi usada como controle.Resultados: A terceira série apresentou maior número de repetições no alongamento estático em comparação ao controle. Além disso, foram verificadas reduções significativas de repetições somente no controle. Entre protocolos, não foram verificadas diferenças no volume de treinamento e percepção subjetiva de esforço.Conclusão: Auto-liberação miofascial e alongamento estático realizados nos músculos antagonistas antes de uma sessão podem manter o desempenho de repetições ao longo das séries a partir de uma recuperação entre séries e redução da fadiga nos músculos agonistas. (AU)

Efeito de diferentes intensidades do exercício antagonista no desempenho de repetições dos agonistas em séries pareadas / Effect of different intensities of antagonist exercise on agonist repetitions performance in paired series

O objetivo do presente estudo foi verificar o efeito agudo de diferentes intensidades em séries pareadas agonistas e antagonistas sobre o desempenho de repetições máximas. Participaram de estudo, 12 homens recreacionalmente treinados (idade: 25.83 ± 3.43 anos; peso: 76.33 ± 5.58 kg; altura 1.72 ± 0.04 metros; IMC: 25.95 ± 1.34 kg/m²). Os procedimentos foram separados em cinco sessões: o primeiro encontro constou de anamnese, medidas antropométricas e teste de 10 repetições máximas (RM) nos exercícios rosca bíceps supinada com barra (RB) e tríceps no pulley (TP). Nos demais encontros, os participantes executaram o máximo de repetições no RB com 80% da carga de 10RM após realizarem, de maneira aleatória e em dias separados, um dos 4 protocolos de diferentes intensidades na musculatura antagonista (TP): Protocolo controle (PC), 10 repetições com 40% de 10RM (P40), 10 repetições com 60% de 10RM (P60) e 10 repetições com 80% de 10RM (P80). Para a análise estatística foi realizada uma ANOVA de medidas repetidas e o nível de significância adotado foi de p < 0.05. Os resultados demonstraram que maiores intensidades (P60 = 15.83 ± 0.94 repetições e P80 = 16.42 ± 0.79 repetições) possibilitaram um aumento significativo (p < 0.05) no desempenho de repetições quando comparado ao PC (14.83 ± 0.72 repetições). Além disso, P80 foi também superior ao P40 (15.25 ± 0.97 repetições, p = 0.00), mostrando existir uma dosagem mínima (60% de 10RM) para a melhora de desempenho no método pareado agonista e antagonista. (AU)

The aim of the present study was to verify the acute effect of different intensities of paired agonist and antagonist series on the performance of maximum repetitions. Twelve recreational trained men participated in the study (age: 25.83 ± 3.43 years; weigth: 76.33 ± 5.58 kg; height 1.72 ± 0.04 meters; IMC: 25.95 ± 1.34 kg/m²). The experimental procedure took place over five sessions: the first consisted of anamnesis, anthropometric measurements and a test of 10 maximum repetitions (RM) in the barbell curved supine (RB) and triceps pulley (TP) exercises. nother meetings, the participants performed maximum repetitions in the RB with 80% of the 10RM load after performing, in random order and on separate days, one of the 4 protocols of different intensities in the antagonist musculature (TP): Control protocol (PC), 10 repetitions with 40% of 10RM (P40), 10 repetitions with 60% of 10RM (P60) and 10 repetitions with 80% of 10RM (P80). For the statistical analysis, an ANOVA was performed and the level of significance adopted was p <0.05. The results showed that higher intensities (P60 = 15.83 ± 0.94 repetitions e P80 = 16.42 ± 0.79 repetitions) enabled a significant increase in repetition performance when compared to CP (14.83 ± 0.72 repetitions). In addition, P80 was also superior to P40 (15.25 ± 0.97 repetitions, p = 0.00), showing that there is a minimum dosage (60% of 10RM) to improve performance in the paired agonist and antagonist method. (AU)

Effects of 12 Months of Vitamin D Supplementation on Physical Fitness Levels in Postmenopausal Women with Type 2 Diabetes.

INTRODUCTION: It is common for postmenopausal women to receive a vitamin D supplementation prescription to assist in preventing future falls and to maintain bone health. However, the association between vitamin D supplementation and physical fitness components has not been studied in older women with diabetes. OBJECTIVE: We examined the influence of 12 months of vitamin D supplementation on the components of physical fitness in postmenopausal women with type 2 diabetes mellitus (T2DM). METHODS: Thirty-five postmenopausal women (62.48 ± 7.67 years; 154.6 ± 5.11 cm; 73.93 ± 15.43 kg; 31.13 ± 5.82 BMI) with a diagnosis of T2DM participated in this longitudinal study where participants were supplemented with 1000 IU/day of vitamin D over 12 months. Subjects performed fasting blood samples, anthropometric assessments, body composition, clinical exams, and physical tests at 6-month intervals (P0, P6, and P12). RESULTS AND CONCLUSION: Vitamin D supplementation alone was effective in postmenopausal women in increasing serum vitamin D levels, altering muscle strength levels, promoting improvements in muscle function, as well as preventing and controlling fragility caused by T2DM and aging.

The Effect of Set Configuration and Load on Post-Activation Potentiation on Vertical Jump in Athletes.

The aim of this study was to compare the effect of post-activation potentiation (PAP) on countermovement jump (CMJ) using different set configurations and loads on conditioning activity (CA) in highly trained athletes. Sixteen national level swimmers participated in this study and performed a total of six visits to the laboratory. The first session was used for familiarization, the second session was utilized to determine five repetitions maximum (RM) in the half squat (HS), and the following four visits consisted of four CA protocols performed in a counterbalanced order. Two CAs were performed as traditional sets (TS) with sequential repetition, with different load, which involved one set of five repetitions at 100% (TS100) or 65% of 5 RM load (TS65). Additionally, two CAs included one set of five repetitions with intraset rests, 30 second inter-repetition rest (IRR), with both relative loads (IRR100 and IRR65). Countermovement jump height was measured at baseline, immediately after the CA, and every two-minutes until twelve-minutes. Significantly faster peak and mean barbell velocity was observed for the CAs with lower relative loads (p < 0.05). When evaluating the best result at individual time point of CMJ height after the CA, TS100 improved CMJ performance (ES = 0.38, p = 0.028, Δ% = 4.8 ± 7.3). Thus, set configuration using IRR does not promote PAP in the current study and TS with a high-load should be adopted for an acute improvement in CMJ for highly trained athletes.

Limited cardiopulmonary capacity in patients with liver cirrhosis when compared to healthy subjects.

OBJECTIVES: The present study compared cardiorespiratory capacity between cirrhotic patients and healthy subjects. METHODS: Nineteen cirrhotic patients and 19 healthy subjects, paired by age and gender, participated in the study. Volunteers performed an incremental cardiopulmonary test with a ramp protocol, a ventilatory and metabolic variables were obtained and analyzed. The recovery was analyzed by calculating the time needed for 50% of oxygen consumption (VO2) recovery to occur as the median between the peak of the exercise and the end of recovery on the VO2 curve (T1/2). The VE/VCO2 slope were performed by the linear regression of ventilation (VE) and carbon dioxide production (VCO2) data. RESULTS: During resting condition, cirrhotic patients presented significantly higher levels of VO2 compared to healthy subjects. The VE/ VO2 and VE/ VCO2 values were significantly higher in the control group at the anaerobic threshold and at the peak of the test compared to cirrhotic patients. Time under effort was significantly higher for healthy subjects. CONCLUSIONS: Based on these findings, it is possible to conclude that liver cirrhosis can compromise the patients' quality of life, mainly by inducing metabolic alterations which can impair functional capacity and lead to a sedentary lifestyle.

Secondary protein in the muscle of exercised rats that received creatine supplementation / Proteína secundaria en el músculo de ratones ejercitados que recibieron suplemento de creatina / Proteína secundária no músculo de ratos exercitados que receberam suplemento de creatina

ABSTRACT Introduction: Currently there is a lack of clarity around the use of Fourier transform infrared (FT-IR) spectroscopy to analyze the effect of creatine (Cr) supplementation on the secondary structures of skeletal muscle tissue protein subjected to exercise. Objective: The objective of this study was to evaluate the spectral characteristics of the tibialis anterior muscle in rats subjected to exercise in a pool and to Cr supplementation. Methods: Experiment 1. First, an experiment was conducted to ensure that FT-IR would be able to detect change in the secondary structures of skeletal muscle tissue protein in the group of sedentary rats (SED) and in the group of rats that received creatine supplementation (CRE). Experiment 2. Next, the effect of physical exercise on the spectral characteristics of muscle tissue, especially when compared to the groups without exercise practice, was examined. Results: It was possible to verify that the peaks centered on 1658 cm-1 (amide I) and 1546 cm-1 (amide II) are characteristic spectra and indicated as markers of protein content. Conclusion: Thus, FT-IR spectroscopy proved to be able to monitor changes in secondary structures of skeletal muscle protein in both animals that received supplements and in those subjected to exercise and both cases reconciled. Furthermore, the FT-IR technique proved to be a viable method for the nondestructive evaluation of skeletal muscle protein structures. Level of evidence II, Investigation of treatment results.

RESUMEN Introducción: Actualmente, no hay claridad en lo que se refiere al uso de la técnica de espectroscopia de Infrarrojo con transformada de Fourier (FT-IR) para análisis del efecto de la suplementación de creatina (Cr) sobre las estructuras secundarias de la proteína del tejido muscular esquelético sometido a ejercicio. Objetivo: El objetivo de este estudio fue evaluar las características espectrales del músculo tibial anterior de ratones sometidos a ejercicio en piscina y a la suplementación con Cr. Métodos: Experimento 1. En primer lugar, fue realizada una experiencia para asegurar que la FT-IR sería capaz de detectar la variación en las estructuras secundarias de la proteína del tejido muscular esquelético en el grupo de ratones sedentarios (SED) y el grupo de ratones que sólo recibieron suplemento de creatina (CRE). Experimento 2. A continuación, fue examinado el efecto del ejercicio físico sobre las características espectrales del tejido muscular, especialmente cuando comparado con los grupos sin práctica de ejercicio. Resultados: Fue posible verificar que los picos centrados en 1658 cm−1 (amida I) y 1546 cm−1 (amida II) son espectros característicos e indicados como marcadores del tenor proteico. Conclusión: Siendo así, la técnica de espectroscopia de FT-IR mostró ser capaz de monitorizar las variaciones en las estructuras secundarias de la proteína del tejido muscular esquelético, tanto en animales que recibieron suplementos, como en los que fueron sometidos a ejercicio y ambos casos conciliados. Además, la técnica FT-IR probó ser un método viable para la evaluación no destructiva de las estructuras proteicas en el músculo esquelético. Nivel de evidencia II, Investigación de los resultados del tratamiento.

RESUMO Introdução: Atualmente, não há clareza no que diz respeito ao uso da técnica de espectroscopia de infravermelho com transformada de Fourier (FT-IR) para análise do efeito da suplementação de creatina (Cr) sobre as estruturas secundárias da proteína do tecido muscular esquelético submetido a exercício. Objetivo: O objetivo deste estudo foi avaliar as características espectrais do músculo tibial anterior de ratos submetidos a exercício em piscina e à suplementação com Cr. Métodos: Experimento 1. Em primeiro lugar, foi realizada uma experiência para assegurar que a FT-IR seria capaz de detectar a variação nas estruturas secundárias da proteína do tecido muscular esquelético no grupo de ratos sedentários (SED) e no grupo de ratos que só receberam suplemento de creatina (CRE). Experimento 2. Em seguida, foi examinado o efeito do exercício físico sobre as características espectrais do tecido muscular, especialmente quando comparado com os grupos sem prática de exercício. Resultados: Foi possível verificar que os picos centrados em 1658 cm−1(amida I) e 1546 cm−1(amida II) são espectros característicos e indicados como marcadores do teor proteico. Conclusão: Assim sendo, a técnica de espectroscopia de FT-IR mostrou ser capaz de monitorar as variações nas estruturas secundárias da proteína do tecido muscular esquelético tanto em animais que receberam suplementos, quanto nos que foram submetidos a exercício e ambos os casos conciliados. Além disso, a técnica FT-IR provou ser um método viável para a avaliação não destrutiva de estruturas proteicas no músculo esquelético. Nível de evidência II, Investigação dos resultados do tratamento.

Myoelectric activity of the gastrocnemius during plantar flexion in a standing versus seated position and with a neutral or dorsiflexed ankle: A pilot study.

OBJECTIVE: The purpose of this study was to investigate the surface electromyographic (EMG) activity of the medial (GM) and lateral (GL) heads of the gastrocnemius muscle during plantar flexion performed in standing or seated positions, and with a neutral or dorsiflexed ankle. INTRODUCTION: The tríceps surae (gastrocnemius and soleus) is an essential muscle group that promotes propulsion during walking, running and tasks of daily living. METHODS: Ten male volunteers (24.5 ± 3.6 years, weight: 75.8 ± 10 kg; height: 1.74 ± 0.07 m) performed ten repetitions of plantar flexion under four different conditions: a) standing position (SP); b) standing position with passive stretch of the gastrocnemius muscle (SPS); c) seated with the knee flexed (KF); d) seated with the knee flexed and a passive stretch of the gastrocnemius (KFS). RESULTS: The muscle activity expressed as the root mean square (RMS) was significantly higher for the GL in the SPS versus the SP condition, while there was no difference for the GM between conditions. However, for the KF condition, GM activity was significantly higher versus the KFS condition, which was not verified for the GL. CONCLUSIONS: Therefore, the standing position with passive stretching of the triceps surae may be more efficient in increasing the myoelectric activity of the GL. However, the sitting position without passive stretching promoted greater GM muscle recruitment. The length/tension relationship of gastrocnemius could be used as a prescription variable during rehabilitation or conditioning programs.

Total Training Volume and Muscle Soreness Parameters Performing Agonist or Antagonist Foam Rolling between Sets.

BACKGROUND: Foam rolling (FR) has become very popular in recent years; however, the practice of FR between sets of resistance training (RT) for the lower limbs needs further examination. PURPOSE: Therefore, the purpose of the present study was to examine the effect of FR for the agonists (quadriceps) and antagonists (hamstrings) between multiple sets of the leg extension on repetition maximum performance (RM), fatigue resistance index (FRI), and muscle soreness (MS). STUDY DESIGN: Quasi-experimental clinical trial. METHODS: Twenty trained men participated in this study (30.35 ± 6.56 years, 1.77 ± 0.05 cm, 87.70 ± 7.6 kg) and attended seven sessions with 48 h between sessions, (one familiarization session; two 10-RM test and retest sessions; and four experimental sessions). The four experimental sessions were performed in random order and included: agonist foam rolling (AFR), antagonist foam rolling (ANTFR), agonist/antagonist foam rolling (A/ANTFR), and traditional control (TP, without foam rolling). All sessions consisted of three sets for maximal repetitions with a 10-RM load for the leg extension. In the AFR and ANTFR sessions, there was a 120 s rest interval between sets, during which FR was done for the agonists or antagonists, respectively. In the A/ANTFR protocol, there was a 120 s rest interval between sets, during which FR was done for the agonists and antagonists. In the traditional protocol (TP), there was a 120 s passive rest interval between sets. RESULTS: Regarding the total training volume (TTV), significant differences were noted between sessions (F3,57 = 11.014; p = 0.0001). The AFR, ANTFR, and A/ANTFR sessions had significantly higher TTV versus the TP (p < 0.05). Regarding the FRI, significant differences were noted between sessions (F3,57 = 2917, p = 0.042). A significantly higher fatigue index was shown for the ANTFR and AFR sessions versus the TP (p < 0.05). Regarding the total number of repetitions, significant differences were noted between sessions (F3,57 = 11.086, p = 0.0001). The total number of repetitions was significantly higher in the A/ANTFR, ANTFR, and AFR versus the TP session (p < 0.05). MS was significantly lower in the A/ANTFR, ANTFR, and AFR sessions versus the TP session (p < 0.05). CONCLUSION: In conclusion, foam rolling between sets for the agonist or antagonist separately or in succession, resulted in greater neuromuscular performance and higher fatigue indices, as well as reducing the perception of acute muscle soreness.