Strength Endurance Performance Research Articles

Preferred Music Genre Benefits During Strength Tests: Increased Maximal Strength and Strength-Endurance and Reduced Perceived Exertion.

The ability to increase muscle strength seems to be influenced by extrinsic factors such as the characteristics of an exercise environment. Given that many people train while listening to music, the music environment is an important research topic. However, no studies have investigated whether a preferred music genre differentially affects strength production when compared to a non-preferred music genre. This study evaluated the influence of listening to varied conditions of musical genre preference on maximal strength and strength-endurance testing, and on ratings of perceived exertion (RPE). We submitted 20 young men to three different listening conditions during strength testing: (a) preferred music genre (PMG), (b) non-preferred music genre (NPMG), and (c) no music (NM), with the order of these conditions randomized. We measured maximal strength with a handgrip dynamometer, strength-endurance through the participant's maximal repetition execution in the lat-pulldown exercise, and RPE by participant-completed Borg's scales at the end of the strength tests. Using three-way analyses of variances (ANOVAs) and a significance level of p < 0.05, we found that participants produced higher maximal strength, performed more repetitions of the lat-pulldown exercise, and reported decreased RPE in the PMG condition, compared to the NPMG (maximal strength p < 0.01, strength-endurance p < 0.01, RPE p = 0.016) and NM (maximal strength p < 0.01, strength-endurance p < 0.01, RPE p = 0.023) conditions. Individually determined PMG appears to improve maximal strength and strength-endurance performance during exercise, and to decrease RPE in the PMG condition.

The Acute Effects of External Compression With Blood Flow Restriction on Maximal Strength and Strength-Endurance Performance of the Upper Limbs.

The main goal of the present study was to evaluate the acute effects external compression with blood flow restriction (BFR) at 100 and 150% of full arterial occlusion pressure (AOP) on maximal strength and strength-endurance performance during the bench press (BP) exercise. The study included 12 strength-trained male subjects (age = 23.2 ± 2.66 years; body mass = 75.3 ± 6.33 kg; height = 179.1 ± 3.82 cm), experienced in resistance training (5.7 ± 2.93 years). During the experimental sessions in a randomized crossover design, the subjects performed a 1 repetition maximum (1RM) test and three sets of the BP using 60% 1RM to failure with three different conditions: without BFR (NO-BFR); BFR with a pressure of 100% AOP (BFR100); and BFR with a pressure of 150% AOP (BFR150). The differences between the NO-BFR, BFR100, and BFR150 conditions were examined using repeated measures ANOVA. The ANOVA indicated significant main effect for condition in 1RM, number of performed repetitions (REP), and time under tension (TUT) (p < 0.01). Post hoc analyses for the main effect indicated significant increases in 1RM (p < 0.01; 95.00 ± 15.37 vs 91.87 ± 15.99), REP (p < 0.01; 17.56 ± 3.36 vs 15.67 ± 5.24), and TUT (p < 0.01; 32.89 ± 6.40 vs 28.72 ± 6.18) for the BFR150 condition compared to NO-BFR. Furthermore, significant increases in REP (p = 0.03; 17.56 ± 3.36 vs 16.47 ± 4.01) and TUT (p = 0.03; 32.89 ± 6.40 vs 30.00 ± 6.45) were observed for the BFR150 condition compared to the BFR100. The results of the present study indicate that high external compression increases maximal strength evaluated by the 1RM test, as well as endurance performance during three sets of the BP exercise.

Differences in Handgrip Strength-Endurance and Muscle Activation Between Young Male Judo Athletes and Untrained Individuals

ABSTRACT Purpose: The aim of this study was to compare strength-endurance handgrip performance and muscle coactivation between judo athletes and untrained young males. Method: The sample was 38 judo athletes and 38 untrained young males, between 12 and 15 years-old. Maturational status was evaluated by age at peak height velocity. A maximal isometric handgrip test (three 5-s repetitions, with 90-s intervals) and an isometric strength-endurance handgrip test (ten 10-s all-out isometric handgrip repetitions, 20-s intervals) was conducted in dominant (D) and nondominant (ND) hands, using a dynamometer with EMG monitor to detect muscle activation. Results: ANCOVA analysis, controlling for maturational status, showed that judo athletes had higher values of maximal absolute (D = 33.6 ± 8.9 kgf vs 29.1 ± 9.0 kgf; ND = 33.8 ± 9.9 kgf vs 28.1 ± 8.1 kgf) and relative strength to body mass (D = 0.64 ± 0.12 kg/kgf vs 0.57 ± 0.13 kg/kgf; ND = 0.64 ± 0.16 kg/kgf vs 0.56 ± 0.14 kg/kgf). Moreover, judo athletes presented lower strength mean fatigue index (33.2 ± 6.9 % vs 37.9 ± 8.7 %) and muscle coactivation (48 ± 19.8 % vs 57.5 ± 22 %), only in the dominant hand, during the isometric strength-endurance handgrip test. During all repetitions of isometric endurance test there were no group or interaction between factors effects for absolute strength, relative strength and muscle coactivation. Conclusion: In summary, judo athletes present higher maximal absolute and relative strength and strength-endurance performance, concomitantly with decreased muscles co-activation (primary in dominant hand) during handgrip tests.

Does the duration of static stretching acutely interferes on the strength endurance performance?

Background: Stretching may promote detrimental effects on power output and maximal strength, but its direct effect on strength endurance remains unclear, as well as the influence of stretching duration. Objective: We aimed to evaluate the direct effect of static stretching of the quadriceps muscle, as well as the stretching duration, on the strength endurance during a unilateral knee extension exercise. Methods: Fifteen strength-trained men (age 28 ± 3 years, height 1.70 ± 0.09 m, body mass 70 ± 5 kg, training experience 5 ± 1 years) took part in a randomized counterbalanced cross-over study. Participants' total number of repetitions was assessed during strength endurance tests (four sets until failure at 70% of one-repetition maximum) performed under three different conditions in separate days: control - no stretching (CON), short-duration stretching (SDS) and long-duration stretching (LDS). Three stretching exercises, with 3 sets lasting 30 seconds each, were performed during SDS, while the number of sets during LDS was doubled. Data were analyzed using mixed models and magnitude-based inferences (MBI). Results: Despite of a significant decrease in the number of repetitions during the strength endurance test performed across the exercise sets (main Set effect p < .001), neither the number of repetitions in each set (main Condition effect p = .95) nor the total number of repetitions (main Condition effect p = .86) were significantly different between the conditions. MBI analysis revealed that changes in the total number of repetitions after SDS and LDS were mainly trivial compared to CON. Conclusions: Regardless of its duration, an acute session of static stretching did not influence strength endurance.

Ischemic Preconditioning Improves Strength Endurance Performance.

Carvalho, L and Barroso, R. Ischemic preconditioning improves strength endurance performance. J Strength Cond Res 33(12): 3332-3337, 2019-Ischemic preconditioning (IPC) has been used to improve performances in aerobic and anaerobic activities. However, a few studies aimed at observing the effects of IPC on resistance training. The purpose of this study is to examine the effects of IPC on the number of repetitions performed during high-load resistance training. We also aimed at investigating blood lactate concentration and muscle activation in an attempt to understand the physiological mechanisms that may be caused by IPC. Ten resistance-trained participants performed four 5-minute cycles of either IPC (250 mm Hg) or Placebo (10 mm Hg) before performing a single set to failure of knee extension exercise with 85% of 1 repetition maximum. We also assessed muscle activation during the set (EMGRMS), median power frequency (EMGMPF), and blood lactate concentration before, 3, 7, and 11 minutes after (peak value was identified and used to calculate delta to prevalues, Δlactate). Data are presented as mean, 90% confidence intervals (CIs), and were analyzed with paired t-test. The level of significance was set at p < 0.05. Participants performed on average 3.9 repetitions (90% CI = 2.4-5.4; p = 0.01), which is ∼20%, more in the IPC condition. There were no significant differences between IPC and Placebo for EMGMPF (5.0%; 90% CI = -5.2 to 15; p = 0.50), EMGRMS (4.5%; 90% CI = -8.8 to 17; p = 0.78), and Δlactate (44%; 90% CI = 11-144; p = 0.16). Our results demonstrate the effect of IPC just on the number of repetitions performed in high-load resistance exercise compared with the Placebo condition.

Manuscript Clarification for Ischemic Preconditioning Improves Strength Endurance Performance.

Manuscript Clarification for Ischemic Preconditioning Improves Strength Endurance Performance.

The Effects of Carbohydrate and Caffeine Mouth Rinse on Upper Body Muscular Strength and Endurance

Carbohydrate (CHO) and caffeine (CAF) are the most preferred nutritional ergogenic aids by elite athletes. CHO improves performance by sparing the muscle glycogen depots and CAF by antagonizing adenosine receptors. In recent years it has been shown that combined or seperated CHO and CAF mouth rinsing can improve sprint performance. However, more research is needed to examine the effect of CHO and CAF rinsing on strength and muscular endurance performance. PURPOSE: to investigate the effect of rinsing of CHO and CAF on bench press strength and endurance performance. METOTS: Twelve resistance trained men participated in this research. After the familiarization test day, participants participated in a total of 4 test days with a randomized, counterbalanced, crossover study design: 6% (1.5 gr.) weight / volume (w / v) CHO mouth rinse (CMR) with 25 ml water, mouth rinse with water (PLA), %1.2 CAF mouth rinse (CAFMR) and combined %6 CHO, %1.2 CAF mouth rinse (CCMR). After a 10-hour night fasting one repetition maximum (1RM) was determined for strength and %40 1RM strength endurance test over a 3 sets until repetition to failure with 2 seconds eccentric and 2 seconds concentric phase. Prior to strength and endurance measurements, participants rinsed the solutions in their mouths for 10 seconds. During the test protocol heart rate (hr), lactate (la), glucose (glu), felt arousal (fa) and ratings of perceived exertion (rpe) were measured. In the analysis of the data, single and two-way repeated measures analysis of variance were used. RESULTS: No significant differences were detected between trials as for strength, endurance, hr, glu, la, fa, rpe (P>0.05). DISCUSSION: This research has shown that orally rinsing of carbohydrate and caffeine does not have a significant effect on upper body strength and muscular endurance performance. The results of the study are in parallel with the literature. In future studies, higher doses of solutions may be rinsed in the mouth to investigate the effect on lower body strength and muscular endurance performance whose which muscle activation percentage is low during maximal voluntary contraction. keywords: Caffeine, carbohydrate, rinsing, ergogenic,

Does the Expectancy on the Static Stretching Effect Interfere With Strength-Endurance Performance?

Bertolaccini, AL, da Silva, AA, Teixeira, EL, Schoenfeld, BJ, and de Salles Painelli, V. Does the expectancy on the static stretching effect interfere with strength-endurance performance? J Strength Cond Res 35(9): 2439-2443, 2021-Static stretching (SS) may interfere with strength performance. Such interference, however, may be partially attributed to the subjects' or researcher's expectancy about the SS effects. We aimed to examine whether the manipulation of subjects' expectancy of SS on force production could influence strength-endurance during unilateral knee extension exercise. Eighteen strength-trained men were randomly divided into positively biased (PB; N = 9) or negatively biased (N = 9) groups on the possible effects of SS on performance. Subjects' total number of repetitions and total volume of exercise were assessed during strength-endurance tests (4 sets performed to failure at 70% of 1 repetition maximum) performed under 2 different conditions on separate days: Control-no stretching (CON); or SS. Static stretching consisted of 3 sets of 3 stretching exercises, lasting 30 seconds each. Data were analyzed using mixed models. Neither the total number of repetitions nor the total volume was significantly different between the CON and SS conditions, nor for type of bias (all p > 0.05). However, the number of repetitions in the last set of exercise was greater during SS compared with CON for the PB group (p = 0.01). Although previous negative or positive information about SS did not interfere with the total number of repetitions and total volume of exercise, previous positive information about SS improved performance in the last set of exercise. Expectancy therefore may have played a partial role influencing strength-endurance in previous studies.

Carbohydrate restriction: Friend or foe of resistance-based exercise performance?

It is commonly accepted that adequate carbohydrate availability is necessary for optimal endurance performance. However, for strength- and physique-based athletes, sports nutrition research and recommendations have focused on protein ingestion, with far less attention given to carbohydrates. Varying resistance exercise protocols, such as differences in intensity, volume, and intraset rest prescriptions between strength-training and physique-training goals elicit different metabolic responses, which may necessitate different carbohydrate needs. The results of several acute and chronic training studies suggest that although severe carbohydrate restriction may not impair strength adaptations during a resistance training program, consuming an adequate amount of carbohydrate in the days leading up to testing may enhance maximal strength and strength-endurance performance. Although several molecular studies demonstrate no additive increases in postexercise mammalian target of rapamycin 1 phosphorylation with carbohydrate and protein compared with protein ingestion alone, the effects of chronic resistance training with carbohydrate restriction on muscle hypertrophy are conflicting and require further research to determine a minimal carbohydrate threshold necessary to optimize muscle hypertrophy. This review summarizes the current knowledge regarding carbohydrate availability and resistance training outcomes and poses new research questions that will better help guide carbohydrate recommendations for strength and physique athletes. In addition, given that success in physique sports is based on subjective appearance, and not objective physical performance, we also review the effects of subchronic carbohydrate ingestion during contest preparation on aesthetic appearance.

Acute effects of aerobic exercise performed with different volumes on strength performance and neuromuscular parameters

The aim of the present study was to investigate the acute effect of the aerobic exercise volume on maximum strength and strength-endurance performance; and possible causes of strength decrements (i.e. central and peripheral fatigue). Twenty-one moderately trained men were submitted to a maximal incremental test to determine anaerobic threshold (AnT) and maximum dynamic strength (1RM) and strength-endurance (i.e. total volume load [TV]) tests to determine their baseline strength performance. Following, subjects performed six experimental sessions: aerobic exercise sessions (continuous running at 90% AnT) with different volumes (3 km, 5 km or 7 km) followed by 1RM or strength-endurance test in the 45° leg press exercise. Maximum voluntary isometric contraction (MVIC), voluntary activation (VA) level, contractile properties, and electromyographic activity (root mean square [RMS]) of the knee extensor muscles were assessed before and after aerobic exercises and after strength tests. TV was lower after 5 km and 7 km runs than in the control condition (12% and 22%, respectively). Additionally, TV was lower after 7 km than 3 km (14%) and 5 km (12%) runs. MVIC, VA, RMS, and contractile properties were reduced after all aerobic exercise volumes (∼8%, ∼5%, ∼11% and ∼6–14%, respectively). Additionally, MVIC, VA, and contractile properties were lower after strength tests (∼15%, ∼6%, ∼9–26%, respectively). In conclusion, strength-endurance performance is impaired when performed after aerobic exercise and the magnitude of this interference is dependent on the aerobic exercise volume; and peripheral and central fatigue indices could not explain the different TV observed.

Does Motivational Music Influence Maximal Bench Press Strength and Strength Endurance?

The purpose of this study is to examine whether motivational music selected by participants has an effect on maximal bench press strength and strength endurance (number of repetitions to failure with a 60% of 1-RM). 26 healthy male students with an average age of 23.92±2.05, average weight of 73.57±4.14 and average height of 178.57±3.65 who were having at least three strength workouts a week participated in the study voluntarily. The participants were grouped in two as experimental group and control group. The measurements of the experimental group were taken in two different sessions as with music and without music with 1 repetition maximum and number of repetitions to failure with 60% of 1 repetition maximum. The two sessions of the control group were conducted without music. At the end of the study, it was found that in experimental group motivational music was not effective on maximal strength (1RM) (p>0.05), while it was found to increase strength endurance statistically by 3.9% (p 0.05). As a conclusion, it is stated that listening to fast music creates an ergogenic acute effect and it is recommended to use music during strength workout to have a better strength endurance performance.

Differences in Anthropometric Characteristics and Physical Capacities Between Junior and Adult Top-Level Handball Players

Background: In all age groups of handball players, anthropometric characteristics and physical capacities are important prerequisites to fulfilling the playing demands. However, there is no study that has compared anthropometric characteristics and physical capacities between junior and adult handball players by the same research design containing field tests. Objectives: This study aimed to investigate differences in anthropometric characteristics and physical capacities between junior and adult top-level handball players using various field tests. Relationships among physical capacities were also examined. Methods: Ten male junior (18 ± 1 years) and eleven adult (26 ± 1 years) field handball players competing in the U19 Bundesliga and DKB Handball-Bundesliga, respectively, were tested for body height, mass, fat, and fat-free mass as well as 30 m speed and 22 m change of direction (COD), squat jump (SJ) and counter movement jump (CMJ), one repetition maximum (1RM) bench press, core strength-endurance, and interval shuttle run test (ISRT). Magnitude-based inferences, effect sizes (ES), and Pearson correlation coefficients (r) were computed for statistical analyses. Results: Juniors had a very likely lower body height, mass, and fat-free mass and likely lower 1RM bench press and ISRT performance (ES: 0.7 - 1.2). Contrary, juniors had a likely to very likely superior speed, COD, and SJ and most likely superior core strength-endurance performance (ES: 0.5 - 1.6). While speed, COD, and jump capacities were large to very large correlated in juniors (r = -0.55 - 0.86), they were mostly unclear correlated in adults (r = -0.05 - 0.79). Overall explained variance among speed, COD, and jump capacities was likely higher in juniors (51%) than adults (17%) (ES: 1.7). Conclusions: This study shows that differences in anthropometric characteristics and physical capacities, and also in relationships among physical capacities, are evident between junior and adult top-level handball players, indicating different physical needs to play handball.

Carbohydrate Mouth Rinse following Fatiguing Resistance Exercise does not Improve Muscle Function

PURPOSE: Carbohydrate mouth rinse has been shown to enhance the performance of endurance exercise. However, the effects of carbohydrate mouth rinse on other types of exercise, including strength and power exercises, have yet to be established. The primary purpose of this study was to assess the effect of carbohydrate mouth rinse on muscular performance after a fatiguing resistance exercise protocol. METHODS: Twenty-one, recreationally resistance trained participants (13 ♀, 8 ♂ Age: 22 ± 2 yr) completed a fatiguing resistance exercise protocol consisting of 8 lower and upper body exercises at 70% of their 1 RM. Volunteers completed the resistance exercise protocol on three occasions, followed by muscle function tests. In a double-blind, randomized, and counterbalanced fashion, each subject was tested under a control (CON) (no rinse), carbohydrate rinse (CHO) (25 ml of 6.4% maltodextrin solution), or placebo rinse (PLC) (non-caloric artificial sweetener placebo solution) condition. During each vertical jump, each attempt at maximal strength (1-RM), and each set of the muscular endurance tests for both the back squat and bench press exercises, subjects rinsed with a CHO or PLC solution for 10 to 15 seconds. ANOVAs were conducted to locate differences between conditions. RESULTS: There were no significant differences in vertical jump (CON = 46.8 ± 9.7, CHO = 48.7 ± 9.7, PLC = 48.0 ± 9.7 cm), maximal strength for back squat (CON = 85.0 ± 41.4, CHO = 87.7 ± 41.1, PLC = 86.6 ± 41.0 kg), and bench press (CON = 56.1 ± 35.7, CHO = 57.4 ± 35.3, PLC = 57.0 ± 35.1 kg) between conditions (p > 0.05). The number of repetitions performed during the back squat (CON = 48 ± 14, CHO = 53 ± 16, PLC = 50 ± 13 repetitions) and bench press (CHO = 44 ± 9, CHO = 49 ± 11, PLC = 48 ± 11 repetitions) muscular endurance tests also did not differ significantly between conditions (p > 0.05). CONCLUSION: Carbohydrate mouth rinsing following a fatiguing resistance exercise protocol does not affect muscular power, maximal strength, or muscular endurance performance.

Carbohydrate and Caffeine Mouth Rinses Do Not Affect Maximum Strength and Muscular Endurance Performance.

Oral carbohydrate (CHO) rinsing has beneficial effects on endurance performance and caffeine (CAF) mouth rinsing either independently or in conjunction with CHO may enhance sprinting performance. However, the effects of CHO and CAF mouth rinses on resistance exercise have not been examined previously. The purpose of this study was to investigate the effects of CHO and CAF rinsing on maximum strength and muscular endurance performance. Fifteen recreationally resistance-trained males completed an exercise protocol, which involved a 1 repetition maximum (RM) bench press followed by 60% of their 1RM to failure in a double-blind, randomized, counterbalanced crossover design. Before exercise, 25 ml of a 6% (15 g; 0.20 ± 0.02 g·kg(-1)) CHO, 1.2% (300 mg; 3.9 ± 0.3 mg·kg(-1)) CAF, carbohydrate with caffeine (C + C) solutions, or water (placebo; PLA) were rinsed for 10 seconds. During the remaining session, no solution was rinsed (control; CON). All solutions were flavored with (200 mg) sucralose. Felt arousal was recorded pre- and post-rinse, and rating of perceived exertion (RPE) was recorded immediately after the repetitions to failure. There were no significant differences in 1RM (p = 0.808; ηp(2)= 0.02), the number of repetitions performed (p = 0.682; ηp(2)= 0.03), or the total exercise volume (p = 0.482; ηp(2)= 0.03) between conditions. Rating of perceived exertion was similar for all trials (p = 0.330; ηp(2)= 0.08), whereas Felt arousal increased as a consequence of rinsing (p = 0.001; ηp(2)= 0.58), but was not different between trials (p = 0.335; ηp(2)= 0.08). These results suggest that rinsing with a CHO and CAF solution either independently or combined has no significant effect on maximum strength or muscular endurance performance.

EFFECTS OF SELF-SELECTED MUSIC ON MAXIMAL BENCH PRESS STRENGTH AND STRENGTH ENDURANCE.

Listening to music during strength workouts has become a very common practice. The goal of this study was to assess the effect of listening to self-selected music on strength performances. Thirty-one resistance-trained men (M age = 24.7 yr., SD = 5.9; M height = 178.7 cm, SD = 4.7; M body mass = 83.54 kg, SD = 12.0) were randomly assigned to either a Music group (n = 19) or to a Control group (n = 12). Both groups took part in two separate sessions; each session consisted in a maximal strength test (1-RM) and a strength-endurance test (repetitions to failure at 60% 1-RM) using the bench press exercise. The music group listened to music in the second assessment session, while the control group performed both tests without music. Listening to music induced a significant increase of strength endurance performance and no effects on maximal strength. These findings have implications for the use of music during strength workouts.

Acute effect of high-intensity aerobic exercise performed on treadmill and cycle ergometer on strength performance.

Concurrent training (i.e., combination of endurance with strength training) may result in negative interference on strength performance. Moreover, there are indications that the magnitude of this interference is dependent on endurance exercise mode. Thus, this study aimed to verify the acute effects of previous running and cycling on strength endurance performance. After the determination of the maximum intensity reached (Imax) during treadmill running and cycle ergometer pedaling and half-squat maximum strength (1 repetition maximum [1RM]), 10 physically active men were submitted to 3 experimental conditions: control condition (S) comprised of 4 sets of maximum repetitions at 80% 1RM, intermittent running (RS), and cycling (CS) conditions (15 × 1 minute:1 minute in the Imax) followed by the strength exercise (S). Maximum number of repetitions (MNR), total session volume (TV), and vastus lateralis electromyographic signal (VLRMS) were analyzed. It was observed that MNR and TV performed in set 1 in the S condition was superior to that performed in set 1 in the RS (p < 0.001) and CS (p < 0.001) conditions; and set 2 in the S condition was superior to set 2 only in the CS for the MNR (p = 0.032) and TV (p = 0.012). For the VLRMS, there was a main effect for repetition, with higher values in the last repetition compared with the second one (p < 0.01). In conclusion, an aerobic exercise bout before strength exercise impairs the subsequent strength endurance performance. In addition, the magnitude of the interference effect was higher after the aerobic cycling exercise.

Creatine supplementation prevents acute strength loss induced by concurrent exercise.

To investigate the effect of creatine (CR) supplementation on the acute interference induced by aerobic exercise on subsequent maximum dynamic strength (1RM) and strength endurance (SE, total number of repetitions) performance. Thirty-two recreationally strength-trained men were submitted to a graded exercise test to determine maximal oxygen consumption (VO2max: 41.56 ± 5.24 ml kg(-1) min(-1)), anaerobic threshold velocity (ATv: 8.3 ± 1.18 km h(-1)), and baseline performance (control) on the 1RM and SE (4 × 80 % 1RM to failure) tests. After the control tests, participants were randomly assigned to either a CR (20 g day(-1) for 7 days followed by 5 g day(-1) throughout the study) or a placebo (PL-dextrose) group, and then completed 4 experimental sessions, consisting of a 5-km run on a treadmill either continuously (90 % ATv) or intermittently (1:1 min at vVO2max) followed by either a leg- or bench-press SE/1RM test. CR was able to maintain the leg-press SE performance after the intermittent aerobic exercise when compared with C (p > 0.05). On the other hand, the PL group showed a significant decrease in leg-press SE (p ≤ 0.05). CR supplementation significantly increased bench-press SE after both aerobic exercise modes, while the bench-press SE was not affected by either mode of aerobic exercise in the PL group. Although small increases in 1RM were observed after either continuous (bench press and leg press) or intermittent (bench press) aerobic exercise in the CR group, they were within the range of variability of the measurement. The PL group only maintained their 1RM. In conclusion, the acute interference effect on strength performance observed in concurrent exercise may be counteracted by CR supplementation.

Effects of an Ultra-Endurance Event on Body Composition, Exercise Performance and Markers of Clinical Health: A Case Study

Objective of the study: The purpose of this case study was to observe the effects of a self-supported ultraendurance mountain cycling event on body composition, lower and upper body muscular endurance, anaerobic capacity, aerobic capacity and markers of clinical health. Materials and methods: A trained endurance cyclist competed in the self-supported ultra-endurance event known as the Tour Divide mountain bike race. The subject cycled the course route twice totaling approximately 8,835 total kilometers over the course of 44 days. Body composition, physical performance, and markers of clinical health were collected pre-race and up to 3-wk post-race. Results: Average total energy intake increased by 1,541 kcals during the race compared to pre-race food consumption. We observed an increase in carbohydrate (113%) and fat (12.85%) intake with a marked decrease in protein consumption (-28%). The subject lost a total of 8.4 kg over the course of the 44-d trek and remained 11.0 kg below pre-race body mass 3-wk post-race. The subject lost fat (7.2 kg) and fat-free mass (1.9 kg.) over the race period, resulting in a 6.4% decrease in body fat. The subject experienced a decrease in absolute VO2 peak, mean power, and peak power measured by a Wingate Anaerobic Capacity Test 96-hrs post-race. Upper and lower body muscular strength endurance performance decreased 96-hrs post-race -15-20 and -20%, respectively. Parameters of liver function, AST and ALT, were elevated immediately post-race (92 and 95%, respectively) and remained 46 and 58% above normative values 96-hrs post-race. Creatine kinase concentration also significantly increased 210% immediately following the race and remained elevated 24 (30%), 48 (46%) and 72-hrs (20%) post-race. Conclusions: We conclude that completing a 44-d extreme ultra-endurance mountain biking race results in a decrease in fat and fat free mass. Additionally, prolonged ultra-endurance performance facilitates decreases in aerobic capacity, anaerobic power, muscular strength endurance as well as increases in markers of muscle damage.

Maximal Strength, Number of Repetitions, and Total Volume Are Differently Affected by Static-, Ballistic-, and Proprioceptive Neuromuscular Facilitation Stretching

Stretching exercises have been traditionally incorporated into warm-up routines before training sessions and sport events. However, the effects of stretching on maximal strength and strength endurance performance seem to depend on the type of stretching employed. The objective of this study was to compare the effects of static stretching (SS), ballistic stretching (BS), and proprioceptive neuromuscular facilitation (PNF) stretching on maximal strength, number of repetitions at a submaximal load, and total volume (i.e., number of repetitions × external load) in a multiple-set resistance training bout. Twelve strength-trained men (20.4 ± 4.5 years, 67.9 ± 6.3 kg, 173.3 ± 8.5 cm) volunteered to participate in this study. All of the subjects completed 8 experimental sessions. Four experimental sessions were designed to test maximal strength in the leg press (i.e., 1 repetition maximum [1RM]) after each stretching condition (SS, BS, PNF, or no-stretching [NS]). During the other 4 sessions, the number of repetitions performed at 80% 1RM was assessed after each stretching condition. All of the stretching protocols significantly improved the range of motion in the sit-and-reach test when compared with NS. Further, PNF induced greater changes in the sit-and-reach test than BS did (4.7 ± 1.6, 2.9 ± 1.5, and 1.9 ± 1.4 cm for PNF, SS, and BS, respectively). Leg press 1RM values were decreased only after the PNF condition (5.5%, p < 0.001). All the stretching protocols significantly reduced the number of repetitions (SS: 20.8%, p < 0.001; BS: 17.8%, p = 0.01; PNF: 22.7%, p < 0.001) and total volume (SS: 20.4%, p < 0.001; BS: 17.9%, p = 0.01; PNF: 22.4%, p < 0.001) when compared with NS. The results from this study suggest that, to avoid a decrease in both the number of repetitions and total volume, stretching exercises should not be performed before a resistance training session. Additionally, strength-trained individuals may experience reduced maximal dynamic strength after PNF stretching.

Efeito agudo dos exercícios de flexibilidade no desempenho de força máxima e resistência de força de membros inferiores e superiores

Este estudo verificou o efeito agudo dos exercícios de flexibilidade estática (EFlex) no desempenho de força máxima (FM) e de resistência de força (RF) em membros inferiores e superiores. Treze voluntários participaram do estudo e foram submetidos a testes de FM e RF (70% 1RM) nos exercícios supino e agachamento precedidos ou não de EFlex. O teste T pareado foi utilizado para comparação das médias nas duas condições. Os EFlex diminuíram a FM no agachamento (141,2±34,2 vs 132±34,9kg; p=0,007) e no supino (77,5±21,7 vs 71,7±17,7kg p=0,04). A RF no agachamento não sofreu efeito dos EFlex (16,2±5,7 vs 16,3±6,8 repetições p=0,48), porém, no supino a RF apresentou diminuição significante (11,7±4,8 vs 9,9±5,1 repetições; p=0,008). Portanto, os EFlex reduziram a FM nos membros inferiores e superiores e a RF somente nos membros superiores. Essa diferença na RF estaria relacionada ao volume de exercícios de flexibilidade pelo tamanho do grupo muscular.