The "arrhythmic" presentation of peripartum cardiomyopathy: case series and critical review of the literature.

Peripartum Cardiomyopathy (PPCM) is a polymorphic myocardial disease occurring late during pregnancy or early after delivery. While reduced systolic function and heart failure (HF) symptoms have been widely described, there is still a lack of reports about the arrhythmic manifestations of the disease. Most importantly, a broad range of unidentified pre-existing conditions, which may be missed by general practitioners and gynecologists, must be considered in differential diagnosis. The issue is relevant since some arrhythmias are associated to sudden cardiac death occurring in young patients, and the overall risk does not cease during the early postpartum period. This is why multimodality diagnostic workup and multidisciplinary management are highly suggested for these patients. We reported a series of 16 patients diagnosed with PPCM following arrhythmic clinical presentation. Both inpatients and outpatients were identified retrospectively. We performed several tests to identify the arrhythmic phenomena, inflammation and fibrosis presence. Cardiomyopathies phenotypes were reclassified in compliance with the updated ESC guidelines recommendations. Arrhythmias were documented in all the patients during the first cardiological assessment. PVC were the most common recorder arrhythmias, followed by VF, NSVT, AF, CSD.

Concealed Substrates in Brugada Syndrome: Isolated Channelopathy or Associated Cardiomyopathy?

Brugada syndrome (BrS) is an inherited autosomal dominant genetic disorder responsible for sudden cardiac death from malignant ventricular arrhythmia. The term "channelopathy" is nowadays used to classify BrS as a purely electrical disease, mainly occurring secondarily to loss-of-function mutations in the α subunit of the cardiac sodium channel protein Nav1.5. In this setting, arrhythmic manifestations of the disease have been reported in the absence of any apparent structural heart disease or cardiomyopathy. Over the last few years, however, a consistent amount of evidence has grown in support of myocardial structural and functional abnormalities in patients with BrS. In detail, abnormal ventricular dimensions, either systolic or diastolic dysfunctions, regional wall motion abnormalities, myocardial fibrosis, and active inflammatory foci have been frequently described, pointing to alternative mechanisms of arrhythmogenesis which challenge the definition of channelopathy. The present review aims to depict the status of the art of concealed arrhythmogenic substrates in BrS, often resulting from an advanced and multimodal diagnostic workup, to foster future preclinical and clinical research in support of the cardiomyopathic nature of the disease.

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.

Maximal strength performance, efficiency, and myoelectric responses with differing intra-set rest intervals during paired set training.

INTRODUCTION: The purpose of this study was to investigate the effect of different rest intervals within paired sets (PS) on total work and training volume, efficiency (training volume load/session duration time), and myoelectric activity. METHOD: Fifteen trained men participated in this study. Four experimental protocols were applied: P30 (30 s rest), P60 (60 s rest), P90 (90 s rest), and P120 (120 s rest). The PS bout consisted of a bench press (BP)/lat pull down (LPD), 30° incline bench press (BP30)/wide-grip seated row (SR), and triceps extension (TE)/biceps curl (BC) exercises. Surface electromyography (sEMG) activity of the biceps and triceps brachii were recorded. RESULTS: Volume load (repetitions x number of exercise sets x loads) was significantly lower for the P30 (5385.8 ±â€¯1224 kg) versus the P60 (6755.6 ±â€¯1398.5 kg), P90 (7358.3 ±â€¯1490.3 kg), and P120 (7463 ±â€¯1310 kg) protocols. No significant differences in sEMG activity was noted between protocols. The efficiency (kg·min-1) of P30 (633.6 ±â€¯144) was significantly higher versus P60 (397.4 ±â€¯82.2), P90 (288.5 ±â€¯58.4), and P120 (219.5 ±â€¯38.5). CONCLUSION: Short intra-set rest intervals (60 s) within PS may be a potential alternative for increasing the volume load, since longer intra-rest (90 s and 120 s) intervals do not provide additional benefits.

Neuromuscular responses for resistance training sessions adopting traditional, superset, paired set and circuit methods.

BACKGROUND: A challenging aspect of research in sports science is designing and conducting studies that simulate actual workout scenarios, especially with application to resistance training (RT). Therefore, the purpose of this study was to compare the effects of RT sessions performed in differing workout formats on myoelectric activity, strength performance, and metabolic markers (creatine kinase, lactate dehydrogenase, blood lactate) over 24, 48 and 72 hours post-workout. METHODS: Twenty-two trained men (25.2±4.1 years, 182.1±12.3 cm and 91.2±5.9 kg) performed the following four training protocols with 10-repetition maximum loads in random order: 1) traditional set (TS): three sets were performed in succession for the barbell bench press (BP), lat pulldown (LPD), 45° incline bench press (BP45), seated close-grip row (SCR), triceps extension (TE) and biceps curl (BC) on a pulley; 2) paired set (PS): three paired sets were performed as follows: BP-LPD, BP45-SCR, and TC-B; 3) super-set (SS): similar to the PS protocol, but without rest between paired exercises; 4) circuit training (CT): one set of each exercise was performed sequentially three times. RESULTS: The results showed greater total volume under the SS (8063.2±2270.5 kg) protocol versus the TS (7356.8±2279.7 kg). Total work (repetitions) was also significantly greater for the SS and CT protocols versus the TS (P<0.05). CONCLUSIONS: Therefore, the practitioners should consider utilizing the SS method during time-constrained periods with the goal to achieve greater training volume in time-efficient manner versus the TS, PS and CT methods.

Knee Frontal Plane Projection Angle: A Comparison Study Between Drop Vertical Jump and Step-Down Tests With Young Volleyball Athletes.

STUDY DESIGN: Observational study. CONTEXT: Altered frontal plane knee mechanics during dynamic tasks have been often associated with lower-extremity injuries. Strategies to decrease these risk factors and improve knee joint stability are often applied in rehabilitation and training environments. OBJECTIVE: The purpose of this study was to compare knee joint frontal plane projection angles (FPPA) via 2-dimensional video analysis during drop vertical jump (DVJ) and step-down test (SDT) tasks in the preferred and nonpreferred limbs of young male and female volleyball players. METHODS: A total of 60 young male (n = 29) and female (n = 31) volleyball players (13.6 [1.1] y, 62.2 [11.2] kg, and 170.8 [10] cm) participated in this study. Once the athletes were screened for inclusion and exclusion criteria, limb preference was operationally defined as the preferred kicking leg or the foot used for stair climbing. In a randomized study design, participants were asked to perform a bilateral DVJ and unilateral step-down landing tasks for both preferred and nonpreferred limb. Kinematic analysis was performed via a 2-dimensional video recording of knee joint FPPA alignment. RESULTS: No difference was noted in FFPA during DVJ and SDT tasks between preferred and nonpreferred limbs in both male and female groups (P > .05). The FFPA was significantly higher for both limbs during DVJ versus SDT in both groups (P ≤ .05), but it was not different between male and female athletes. CONCLUSIONS: Based on these findings, clinicians may expect young male and female volleyball athletes to demonstrate similar and symmetrical lower-extremity 2-dimensional knee joint FPPA values across screening tests intended to identify lower-extremity injury risk factors. However, greater FPPA values should be expected during the more dynamic DVJ task.

Postexercise Hypotension and Heart Rate Variability Responses Subsequent to Traditional, Paired Set, and Superset Resistance Training Methods.

Paz, GA, Iglesias-Soler, E, Willardson, JM, Maia, MdF, and Miranda, H. Postexercise hypotension and heart rate variability responses subsequent to traditional, paired set, and superset resistance training methods. J Strength Cond Res 33(9): 2433-2442, 2019-The purpose of this study was to compare training volume, postexercise hypotension (PEH), and heart rate variability (HRV) responses to different strength training methods. Thirteen trained men volunteered for this study. Three training methods were completed in a randomized design, which included: Traditional Set (TS)-3 successive sets for the lying bench press (LBP), lat pulldown (LPD), incline 45° bench press (BP45), seated close-grip row (SCR), triceps extension (TE), and biceps curl (BC), with a 90-second rest interval between sets and exercises; Paired Set (PS)-3 paired sets for the LBP-LPD, BP45-SCR, and TE-BC, with a 90-second rest interval between sets and exercises; and superset (SS)-3 supersets for the LBP-LPD, BP45-SCR, and TE-BC. During the SS session, no rest was permitted between PSs, followed by 180 seconds of rest after each SS. Ten repetition-maximum (RM) loads were adopted for all exercises. Blood pressure (BP) and HRV were measured at baseline, immediately aftersession, and at 10-minute intervals until 60 minutes after session. Significantly greater training volume was noted under the SS method (8,608.6 ± 2,062.2 kg) vs. the TS method (7,527.5 ± 2,365.1 kg), respectively. Significantly greater training volume was also observed under the PS method (8,262.3 ± 2,491.2 kg) vs. the TS method (p ≤ 0.05). No main effects for HRV and PEH were noted between protocols (p > 0.05). However, similar PEH response intraprotocols were observed for the TS, PS, and SS methods (p ≤ 0.05). Considering the duration of the PEH intraprotocol, large effect sizes were noted for the SS and PS methods vs. the TS method in diastolic and mean BP. Therefore, both the PS and SS methods may be an alternative to the TS method to achieve greater total repetitions and training volume with a tendency toward a longer PEH response.

Myoeletric indices of fatigue adopting different rest intervals during leg press sets.

INTRODUCTION: The purpose of this study was to examine the acute effect of different rest intervals between multiple sets of the 45° angled leg press exercise (LP45) on surface electromyographic (SEMG) spectral and amplitude indices of fatigue. METHODS: Fifteen recreationally trained females performed three protocols in a randomized crossover design; each consisting of four sets of 10 repetitions with 1 (P1), 3 (P3), or 5 (P5) minute rest intervals between sets. Each set was performed with 70% of the LP45 ten-repetition maximum load. The SEMG data for biceps femoris (BF), vastus lateralis (VL), vastus medialis (VM), and rectus femoris (RF) muscles was then evaluated. RESULTS: The SEMG amplitude change in the time coefficient (CRMS) and spectral fatigue index (Cf5) indicated higher levels of fatigue for all muscles evaluated during the P3 protocol versus the P1 and P5 protocols (p ≤ 0.05), respectively. The RF and VL muscles showed greater fatigue levels by the second and third sets; whereas, greater fatigue was shown in the VM and BF muscles by the fourth set (p ≤ 0.05). CONCLUSIONS: A three-minute rest interval between sets might represent a neuromuscular window between a fatigue stated and fully recovered state in the context of neural activation. Moreover, a three minute rest interval between sets might allow for consistent recruitment of high threshold motor units over multiple sets, and thus promote a more effective stimulus for strength gains.

Repetition Performance and Blood Lactate Responses Adopting Different Recovery Periods Between Training Sessions in Trained Men.

Miranda, H, Maia, MF, Paz, GA, de Souza, JAAA, Simão, R, Farias, DA, and Willardson, JM. Repetition performance and blood lactate responses adopting different recovery periods between training sessions in trained men. J Strength Cond Res 32(12): 3340-3347, 2018-The purpose of this study was to examine the effect of different recovery periods (24, 48, and 72 hours) between repeated resistance training (RT) sessions for the upper-body muscles on repetition performance and blood lactate responses in trained men. Sixteen recreationally trained men (age: 26.1 ± 3.1 years; height: 179 ± 4.5 cm; body mass: 82.6 ± 4.0 kg, 4.5 ± 2.2 years of RT experience) participated in this study. Eight repetition maximum (8RM) loads were determined for the bench press (BP), 30° incline bench press (BP30), and 45° incline bench press (BP45) exercises. To assess the effects of different recovery periods between repeated training sessions, 3 protocols were performed in randomized order, including 24 hours (P24), 48 hours (P48), and 72 hours (P72). Each RT session consisted of performing 4 repetition maximum sets of the BP, BP30, and BP45 with 8RM loads and 2-minute rest intervals between sets. Blood lactate levels were measured presession (PRE), immediately postsession (POST), 3 minutes postsession (P3), and 5 minutes postsession (P5). For the P24 protocol, significant decreases in repetition performance were found between sessions for the BP, BP30, and BP45 exercises, respectively. When considering session 2 only, the total work (repetition × sets) was significantly higher under P48 and P72 compared with P24 for the BP30 and BP45 exercises. Blood lactate levels (i.e., POST, P3, and P5) significantly increased for session 2 under the P24 compared with the P48 and P72 protocols, respectively. Therefore, coaches and practitioners who need to accomplish a higher training volume for the upper-body muscles should adopt recovery periods longer than 24 hours between sessions that train the same or similar muscle groups.

Hypotensive Responses of Reciprocal Supersets versus Traditional Resistance Training in Apparently Healthy Men.

The purpose of this study was to compare the hypotensive responses of reciprocal supersets (SS) versus traditional training (TRAD) methods. Thirteen men with at least five years of recreational experience in resistance training (RT) volunteered for the study. When completing the TRAD protocol, participants performed the following exercises separately in sequence: chest press (CP), low row (LR), leg extension (LE), leg curl (LC), pull down (PD), and shoulder press (SP). The SS method required participants to complete the same exercises as in the TRAD protocol, but exercises were coupled such that muscles sequentially served both as an agonist for lift one and then antagonist for lift two and vice versa. Exercise order used was CP and LR, LE and LC, and PD and SP with 10 repetition maximum loads. Blood pressure (BP) was measured before and for every 10 minutes for one hour after training. There was significantly more total work (TW) done in the TRAD condition compared to SS. Post exercise hypotension was evident only after the TRAD session at minutes 30 and 40 for systolic BP. Significant differences between the TRAD and SS methods were found at 20 minutes, 30 minutes, and 40 minutes for systolic BP. There was no significant two-way interaction for group × time for diastolic BP. There was a significant two-way interaction for group × time for mean arterial pressure. Significant reductions for mean arterial pressure (MAP) occurred only in the TRAD method after 30 to 40 minutes compared to the baseline values. Therefore, a TRAD RT method was sufficient to cause a hypotensive effect after the training session whereas the SS method did not reveal significant decreases in BP after the session. However, these findings are important to elucidate concerns regarding the post-exercise hypotension after RT and showed that TW might be the key to promote these changes because the volume of training was shown to be an important training variable to manipulate and might be associated with BP hypotension after RT.

Myoeletric Activity of the Quadriceps During Leg Press Exercise Performed With Differing Techniques.

Machado, W, Paz, G, Mendes, L, Maia, M, Winchester, JB, Lima, V, Willardson, JM, and Miranda, H. Myoeletric activity of the quadriceps during leg press exercise performed with differing techniques. J Strength Cond Res 31(2): 422-429, 2017-The quadriceps muscle supplies the motive force for dynamic knee extension. During this action, the vastus medialis oblique (VMO) and vastus lateralis (VL) co-contract to stabilize the patella as it tracks within the patellofemoral groove. The purpose of this study was to analyze surface electromyographic (SEMG) responses for the VL, VMO, rectus femoris (RF), and biceps femoris (BF), as well as the VMO:VL ratio during an open-kinetic chain 45° angled leg press (LP45). The traditional LP45 technique was compared with 2 alternative LP45 exercise techniques that used a physioball and elastic band, respectively. Thirteen female college students performed 3 protocols in random order: TRAD-1 LP45 set performed using the traditional exercise technique, PBALL-1 LP45 set performed with a physioball held between the knee joints, and PEB-1 LP45 set performed with an elastic band proximal to the knee joints. Ten repetitions at 70% of a 10 repetition maximum load were performed in each protocol, and the SEMG data were recorded for the VMO, VL, RF, and BF muscles. Significant increases in VMO activity were noted during PBALL vs. PEB (p = 0.001) and TRAD (p = 0.002). Higher VMO activity was noted during TRAD vs. PEB (p = 0.001). Greater VL activity was noted during PBALL vs. TRAD (p = 0.0001) and PEB (p = 0.0001). The PBALL condition elicited a greater VMO:VL ratio during the concentric phase vs. the PEB (p = 0.001) and TRAD (p = 0.001) protocols. Greater RF activity was observed during PEB vs. TRAD (p = 0.001) and PBALL (p = 0.001). Therefore, practitioners should consider placing a physioball between the knees during the LP45 exercise as an alternative technique when greater overall quadriceps activity is desired for clinical rehabilitation or a muscle strengthening program.

Physical performance and positional differences among young female volleyball players.

BACKGROUND: The purpose of this study was to investigate the association among anthropometric, physical performance parameters, and dynamic postural control attributes of young female volleyball athletes, and to determine if differences exist in these attributes according to playing position. METHODS: Forty-three young female volleyball players participated in this study. Players were divided by position into hitters (N.=17), middle blockers (N.=8), setters (N.=10), and liberos (N.=8). Stature, body mass, vertical jump (VJ), peak power, horizontal jump (HJ), sit-and-reach (SRT), star excursion balance (SEBT), and agility (e.g. shuttle run and Illinois agility test) tests were assessed on non-consecutive days in randomized order. RESULTS: No difference was found between groups for SRT, peak power, VJ, and HJ (P≤0.05). Middle blockers and hitters were taller than setters (P≤0.05). Middle blockers were also taller than liberos (P=0.017). Significant differences were observed among groups for agility tests, with hitters significantly faster than setters (P=0.023) and middle blockers (P=0.037). In addition, liberos were significantly faster than setters (P=0.032) and middle blockers (P=0.046), during the Illinois agility test. No difference was observed between groups for reach distance scores in the SEBT. CONCLUSIONS: These results demonstrate important positional differences in agility measures of young female volleyball players. Coaches can use this information to determine the type of physical profile that is needed for specific positions and to design training programs to maximize strength, power, and neuromuscular development of young female volleyball athletes.

Electromyography Activation of the Lower-Limb Muscles Adopting a Physioball and Elastic Band to Stabilize the Knee Joint During Multiple Sets With Submaximal Loads.

STUDY DESIGN: Crossover design. CONTEXT: Excessive valgus and varus force which affected the knee joint during dynamic tasks has been often associated to lower extremity injuries. Strategies to increase the resistance against these asymmetries (eg, the use of a physioball between the knees or elastic bands around the knees) are often applied in rehabilitation and conditioning programs. OBJECTIVE: The purpose of this study was to investigate the effect of performing leg press (LP) 45° using a physioball and elastic band over multiple sets with submaximal loads on electromyographic (EMG) amplitude and fatigue indices. METHODS: 18 trained females volunteered (age: 24.4 ± 2.1 y; height: 168.1 ± 4 cm; body mass: 65.1 ± 4.4 kg) participated in this study. The 10 repetition maximum (RM) loads were determined for the LP. Then, 3 experimental protocols were followed in a randomized crossover design over 3 nonconsecutive days: control protocol-the participants performed 4 LP sets; physioball between knees-4 LP sets were performed with the physioball between the knees; elastic band-4 LP sets were performed with the elastic band involving the knees. Ten repetitions were performed during each set with 70% of 10-RM loads; EMG spectral indices (CRMS and Cf5) was collected from the biceps femoris (BF), vastus lateralis (VL), vastus medialis obliquus (VMO), and rectus femoris (RF) muscles. RESULTS: Higher levels of CRMS and Cf5 were noted for RF, VL, and VM muscles using the physioball and elastic band when compared with control protocol, respectively. CRMS index of BF muscle was significantly higher using physioball and elastic band protocol versus control condition, respectively. CONCLUSION: Therefore, both physioball and elastic band can be adopted during LP with the goal to reduce excessive varus and valgus forces, respectively, even performing consecutive sets with submaximal loads. Furthermore, this may be an interesting alternative to increasing quadriceps activation and improving the knee joint stabilization.

KINEMATIC ANALYSIS OF KNEE VALGUS DURING DROP VERTICAL JUMP AND FORWARD STEP-UP IN YOUNG BASKETBALL PLAYERS.

PURPOSE/BACKGROUND: Lower limb asymmetry between dominant and nondominant limbs is often associated with injuries. However, there is a lack of evidence about frontal plane projection angle (FPPA) of the knee joint (knee valgus) during drop vertical jump (DVJ) and forward step-up tasks (FSUP) in young basketball players. Therefore, the purpose of this study was to assess the FPPA (i.e., dynamic knee valgus) via 2D video analysis during DVJ and FSUP tasks in the dominant and nondominant limbs of young male basketball players. METHODS: Twenty seven young male basketball players (age 14.5 ± 1.3 y, height 161.1 ± 4.1 cm, weight 64.2 ± 10.2 kg) participated in this study. The participants were asked to perform a bilateral DVJ and unilateral FSUP tasks. Kinematic analysis of FPPA was completed via a two-dimensional (2D) examination in order to evaluate the knee valgus alignment during the beginning of the concentric phase of each task. Knee valgus alignment was computed considering the angle between the line formed between the markers at the anterior superior iliac spine and middle of the tibiofemoral joint and the line formed from the markers on the middle of the tibiofemoral joint to the middle of the ankle mortise. Paired t-tests were used to evaluate differences in tasks. Standard error of measurement (SEM) was calculated to establish random error scores. RESULTS: There was no difference in knee valgus angle during the DVJ task between dominant (20.2 ± 4.4 º) and nondominant legs (20 ± 4.1 º; p = 0.067). However, a significant difference was noted during FSUP between the non-dominant limb (18.7 ± 3.4 º) when compared to the dominant (21.7 ± 3.5 º; p = 0.001) limb. CONCLUSION: Two dimensional kinematic analysis of knee FPPA may help coaches and other professionals to detect asymmetries between dominant and nondominant limbs, and to develop training programs with the goal of reducing overall lower extremity injury risk. LEVEL OF EVIDENCE: 2b.

Efeito da pré-ativação dos antagonistas sobre a determinação da carga no teste de 10 repetições máximas no exercício supino reto / Effects of antagonist pre-activation on 10 repetition maximum load determination in the bench press exercise

Introdução: Evidências indicam que a pré-ativação do antagonista melhora o desempenho agonista no exercício. Objetivo: Verificar o efeito da pré-ativação dos antagonistas (PAA) na determinação de carga no teste de 10 repetições máximas (RM) no supino reto no smith (SRS). Métodos: sessões 1 e 2, o teste e reteste de 10-RM foram aplicados no exercício remada aberta sentado (RAS). Sessões 3, 4, 5 e 6, o teste e reteste para o exercício SRS foram aplicados em duas condições distintas: tradicional, sem pré ativação dos antagonistas; PAA, uma série no RAS foi aplicada até a falha, e seguida pela tentativa no exercício SRS registrando-se o máximo de carga para de 10-RM. Resultado: no exercício SRS sem PAA obteve-se 99 ± 10,5 kg, quando se realizou a PAA através da RAS verificou-se 102,7 ± 12,7 kg. Conclusão: o estudo evidenciou que a pré-ativação dos antagonistas pode aumentar a força dos agonistas melhorando seu desempenho.

Introduction: studies indicate that preactivation of the antagonist can improve performance on agonist exercise. Objective: investigate the effect of antagonist preactivation (PAA) on the 10 maximum repetition performance of the agonists. Methods: on sessions 1 and 2, the volunteers performed a test and retest of 10 maximum repetitions (RM) in the wide grip seated row (WSR). Sessions 3, 4, 5 and 6, a test and retest in the bench press in smith machine (BPS) was made in two conditions: traditional, without preactivation; PAA, one set in the WSR to the fatigue point and immediately a trial in the BPS every attempt, registering the maximum 10-RM load. Results: the BPS test without PAA was obtained 99 ± 10.5 kg, however when PAA was carried out in SR test was obtained 102.7 ± 12.7 kg. Conclusion: The study showed that the proposal to activate the antagonist before agonist may increase the strength of the agonist.

Desempenho de repetições máximas adotando diferentes ordens de exercícios em uma sessão de treinamento de força para o membro superior / Performance of maximum number of repetitions for different variations of exercise order in an upper limb resistance training session

Introdução: A ordem dos exercícios interfere diretamente no desempenho de força. Objetivo: Investigar a influência de diferentes ordens de execução de exercícios em uma sessão de treinamento de força sobre o desempenho de repetições. Métodos: Dezoito homens treinados realizaram dois protocolos experimentais randomizados: SEQA ­ supino reto (SR), supino inclinado (SI), desenvolvimento na máquina (DM), abdução de ombros (AO), tríceps pulley (TP) e tríceps francês (TF); SEQB ­ ordem inversa. Três séries com cargas de dez repetições máximas foram realizadas para todos os exercícios. Resultados: Observaram-se diferenças significativas no trabalho total (repetições x séries) para os exercícios SR, SI, DM, AO, e TF entre SEQA e SEQB, exceto no TP. Não houve diferenças significativas entre as sequências (p = 0,07), considerando o somatório de repetições para SEQA (2225 ± 2,44) e SEQB (2337 ± 3,02). Conclusão: Sugere-se que os exercícios prioritários sejam realizados no início da sessão de treinamento, independente do tamanho do grupo muscular.

Introduction: The exerciser order directly affects the strength performance. Objective: To investigate the influence of different variations of exercise order on repetition performance during resistance training sessions. Methods: Eighteen trained men performed two randomized experimental protocols: SEQA ­ bench press (BP), incline bench press (IBP), machine shoulder press (MSP), shoulders abduction (SA), triceps extension on pulley (TEP) and French triceps extension (FTE); SEQB ­ reverse order. Three repetitions to failure sets were performed with ten repetition maximum loads for all exercises. Results: Significant differences were observed in total work (repetitions x sets) for BP, IBP, MSP, SA, and FTE between SEQA and SEQB, except TEP exercise. There were no significant differences between the sequences (p = 0.07), considering the sum of repetitions for all exercises under SEQA (2225 ± 2.44) and SEQB (2337 ± 2.3). Conclusion: We suggest that priority exercise should be performed in the beginning of the training session, regardless the muscle group size.

Influência da ordem dos exercícios no desempenho do número de repetições com baixa intensidade de carga em homens destreinados / Influence of exercise order on repetition performance with low intensity resistance in untrained men

INTRODUÇÃO: A ordem dos exercícios pode afetar significativamente o desempenho de força muscular. OBJETIVO: Comparar o desempenho de repetições máximas e percepção subjetiva de esforço adotando diferentes ordens de exercícios. MÉTODOS: Trinta e seis homens destreinados (27,86 ± 2,89 anos) realizaram duas sessões, a saber: SEQA ­ com a seguinte sequência: supino reto (SR), puxada alta (PA), desenvolvimento (DS), rosca bíceps (RB), rosca tríceps (RT), leg press (LP), cadeira extensora (CE) e mesa flexora (MF); e SEQB ­ com ordem inversa adotada para RT, RB, DS, PA, SR, MF, CE, LP. RESULTADOS: Os exercícios SR, PA, RB e RT mostraram valores significativamente maiores no número total de repetições na SEQA. Quanto a MF, CE, LP, não houve diferença significativa. A percepção sub-jetiva de esforço apresentou diferença para os seguintes exercícios: MF, RB e RT entre as sequências. CONCLUSÃO: Dessa forma, os grupos musculares priorizados devem ser exercitados no início das sequências.

INTRODUCTION: Exercise order may significantly affect muscle strength per-formance. OBJECTIVE: To compare the maximum repetition performance and perceived exertion adopting different orders exercises. METHODS: Thirty-six untrained men (27.86 ± 2.89 years) performed two exercise sequences: SEQA ­ the order was: bench press (BP), lat pull down (LPD), shoulder press (SP), biceps curl (BC), triceps curl (TC), leg press (LP), leg extension (LE) and leg curl (LC); SEQB ­ the reverse order was adopted to TC, BC, SP, LPD, BP, LC, LE, LP. Results: BP, LPD, BC and TC repetition performance was significantly higher during SEQA when compared to SEQB. However, no differences were noted for LC, LE and LP. The perceived exertion showed differences for the following exercises: LC, BC and TC. CONCLUSION: Therefore, the main muscle groups should be exercised at the beginning of training session

Acute effects of antagonist static stretching in the inter-set rest period on repetition performance and muscle activation.

The purpose of this study was to investigate the effects of antagonist passive static stretching (AS) during the inter-set rest period on repetition performance and muscle activation. Ten trained men (22.4 ± 0.9 years) participated in this study. Two protocols were adopted: Passive recovery (PR)--three sets to repetition failure were performed for the seated row (SR) with two-minute rest interval between sets without pre-exercise stretching; AS--forty seconds of stretching was applied to pectoralis major prior to each set of SR. Significant increases in the number of repetitions were noted under AS compared with PR (p < 0.05). Significant increases on latissimus dorsi (p = 0.002) and biceps brachii (p = 0.001) muscle activity were noted inter-sets under the AS compared with the PR condition. Therefore, the AS adopted during the inter-set rest period may enhance repetition performance and activation of agonist muscles in an acute manner.

Maximal repetition performance, rating of perceived exertion, and muscle fatigue during paired set training performed with different rest intervals.

BACKGROUND/OBJECTIVE: The purpose of this study was to examine rest interval length between agonist-antagonist paired set training (PS) on maximal repetition performance, rating of perceived exertion, and neuromuscular fatigue. METHODS: Fourteen trained men (age, 24.2 ± 1.1 years; height, 175 ± 5.5 cm; body mass, 76.6 ± 7.0 kg) performed two experimental protocols in random order with 2 minutes (P2) or 4 minutes (P4) between agonist-antagonist PS, which consisted of a bench press set followed immediately by a seated row set with 8-repetition maximum loads, respectively. A total of three PS were performed for each rest interval protocol. The total repetitions performed and the rating of perceived exertion were recorded for each exercise set within each rest interval protocol. Electromyography signals were recorded for the posterior deltoid, biceps brachii, pectoralis major, and triceps brachii muscles during the SR exercise. The electromyography signals were then used to calculate a fatigue index for each rest interval protocol. RESULTS: No significant differences were identified in the total repetitions completed between rest interval protocols for the bench press (P2 = 22.9 ± 1.3 and P4 = 22.6 ± 0.8) and seated row (P2 = 25.4 ± 1.7 and P4 = 25.1 ± 1.3). However, a significantly higher fatigue index was found for all muscles under the P2 versus the P4 protocol. CONCLUSION: When performing agonist-antagonist PS, prescribing a shorter rest interval between PS may induce higher levels of fatigue, albeit with similar total repetitions versus a longer rest interval.

Effects of different rest intervals between antagonist paired sets on repetition performance and muscle activation.

Recent evidence suggests that exercising the antagonist musculature acutely enhances subsequent performance for the agonist musculature. The purpose of this study was to examine the effects of different rest intervals between sets for exercises that involve antagonistic muscle groups, a technique referred to as antagonist paired sets (APS). Fifteen recreationally trained men were tested for knee extension (KE) exercise performance, with or without previous knee flexion (KF) exercise for the antagonist musculature. The following protocols were performed in random order with 10 repetition maximum loads for the KF and KE exercises: (a) traditional protocol (TP)-1 set of KE only to repetition failure; (b) paired sets with minimal allowable rest (PMR)-1 set of KF followed immediately by a set of KE; (c) P30-30-second rest between paired sets of KF and KE; (d) P1-1-minute rest between paired sets; (e) P3-3-minute rest between paired sets; and (f) P5-5-minute rest between paired sets. The number of repetitions performed and electromyographic (EMG) activity of vastus lateralis, vastus medialis (VM), and rectus femoris (RF) muscles were recorded during the KE set in each protocol. It was demonstrated that significantly greater KE repetitions were completed during the PMR, P30, and P1 protocols vs. the TP protocol. Significantly greater EMG activity was demonstrated for the RF muscle during the KE exercise in the PMR and P30 vs. the TP, P3, and P5, respectively. In addition, significantly greater EMG activity was demonstrated for the VM muscle during the PMR vs. all other protocols. The results of this study indicate that no rest or relatively shorter rest intervals (30 seconds and 1 minute) between APS might be more effective to elicit greater agonist repetition enhancement and muscle activation.