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Caffeine is a well-described ergogenic aid used to enhance athletic performance. Using animal models can greatly increase our understanding of caffeine's mechanisms in performance. Here, we adapted an animal weight-lifting exercise model to demonstrate caffeine's ergogenic effect in rats. Male Wistar rats (315 ± 35 g) were randomly divided into two groups: one group received 5 mg·kg-1 of caffeine (0.5 mL; CEx; n = 5) and the other 0.9% NaCl (0.5 mL; PEx; n = 4) through an orogastric probe (gavage) one hour before exercise. Weight-lifting exercise sessions were performed over three subsequent days, and the number of complete squats performed was counted. Analyses of the area under the curve in all three experiments showed that the CEx group responded more to stimuli, performing more squats (1.7-, 2.0-, and 1.6-fold; p < 0.05) than the control group did. These three days' data were analyzed to better understand the cumulative effect of this exercise, and a hyperbolic curve was fitted to these data. Data fitting from the caffeine-supplemented group, CEx, also showed larger Smax and Kd (2.3-fold and 1.6-fold, respectively) than the PEx group did. Our study demonstrated an acute ergogenic effect of caffeine in an animal weight-lifting exercise model for the first time, suggesting potential avenues for future research.

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NOVELTY: This study is novel in classifying bodybuilding posing training as vigorous intensity exercise using metabolic equivalents (METs) and heart rate (HR) responses. It provides empirical evidence showing that posing training meets the vigorous intensity benchmarks, with METs and %HRmax values comparable to established vigorous exercise standards. The research highlights the novel finding that stimulant usage and the peak week phase of preparation significantly influence physiological responses and perceived exertion in bodybuilders. Specifically, athletes using stimulants and those in peak week displayed higher ratings of perceived exertion (RPE) and maximum heart rates, indicating that these factors notably affect the intensity and perceived difficulty of posing training.

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This study investigated the effects of different resistance training (RT) volumes quantified by weekly sets at high intensity (load and effort) on dynamic strength adaptations and psychophysiological responses in trained individuals. Twenty-four athletes were randomly allocated to three groups that performed three (3 S, n=8), six (6 S, n=8), and nine (9 S, n=8) weekly sets, respectively, three times a week on the barbell back squat and bench press during an 8-week period. While all groups showcased strength gains (p<0.05), post hoc comparisons revealed that 6 S and 9 S elicited greater strength adaptations than 3 S in barbell back squat (p=0.027 and p=0.004, respectively) and bench press (p=0.001 and p=0.044, respectively). There were no differences between 6 S and 9 S conditions for back squat (p=0.999) and bench press (p=0.378). Although a time effect was observed for Session-RPE (p=0.014) and Total Quality Recovery scale (p=0.020), psychophysiological responses were similar among groups. Our findings suggest that performing six and nine weekly sets at high intensities led to greater strength gains compared to three weekly sets in strength-trained individuals, despite similar psychophysiological responses.

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ABSTRACT: Corrêa Neto, VG, Silva, DdN, Palma, A, de Oliveira, F, Vingren, JL, Marchetti, PH, da Silva Novaes, J, and Monteiro, ER. Comparison between traditional and alternated resistance exercises on blood pressure, acute neuromuscular responses, and rating of perceived exertion in recreationally resistance-trained men. J Strength Cond Res 38(5): e211-e218, 2024-The purpose of this study was to compare the acute effects of traditional and alternated resistance exercises on acute neuromuscular responses (maximum repetition performance, fatigue index, and volume load), rating of perceived exertion (RPE), and blood pressure (BP) in resistance-trained men. Fifteen recreationally resistance-trained men (age: 26.40 ± 4.15 years; height: 173 ± 5 cm, and total body mass: 78.12 ± 13.06 kg) were recruited and performed all 3 experimental conditions in a randomized order: (a) control (CON), (b) traditional (TRT), and (c) alternated (ART). Both conditions (TRT and ART) consisted of 5 sets of bilateral bench press, articulated bench press, back squat, and Smith back squat exercises at 80% 1RM until concentric muscular failure. The total number of repetitions performed across sets in the bench press followed a similar pattern for TRT and ART, with significant reductions between sets 3, 4, and 5 compared with set 1 (p < 0.05). There was a significant difference for set 4 between conditions with a lower number of repetitions performed in the TRT. The volume load was significantly higher for ART when compared with TRT. TRT showed significant reductions in BP after 10-, 40-, and 60-minute postexercise and when compared with CON after 40- and 60-minute postexercise. However, the effect size illustrated large reductions in systolic BP during recovery in both methods. Thus, it is concluded that both methods reduced postexercise BP.

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Incorrect limb position while lifting heavy weights might compromise athlete success during weightlifting performance, similar to the way that it increases the risk of muscle injuries during resistance exercises, regardless of the individual's level of experience. However, practitioners might not have the necessary background knowledge for self-supervision of limb position and adjustment of the lifting position when improper movement occurs. Therefore, the computerized analysis of movement patterns might assist people in detecting changes in limb position during exercises with different loads or enhance the analysis of an observer with expertise in weightlifting exercises. In this study, hidden Markov models (HMMs) were employed to automate the detection of joint position and barbell trajectory during back squat exercises. Ten volunteers performed three lift movements each with a 0, 50, and 75% load based on body weight. A smartphone was used to record the movements in the sagittal plane, providing information for the analysis of variance and identifying significant position changes by video analysis (p < 0.05). Data from individuals performing the same movements with no added weight load were used to train the HMMs to identify changes in the pattern. A comparison of HMMs and human experts revealed between 40% and 90% agreement, indicating the reliability of HMMs for identifying changes in the control of movements with added weight load. In addition, the results highlighted that HMMs can detect changes imperceptible to the human visual analysis.

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Engagement in physical activity, across various sports, promotes a diverse microbiota in active individuals. This study examines the gut microbiota of Colombian athletes, specifically weightlifters (n = 16) and road cyclists (n = 13), compared to non-athletes (n = 15). Using Kruskal-Wallis tests, the physical activity level of a group of non-athletic individuals and the sports experience of a group of professional athletes is analyzed. The median age of participants is 24 years, comprising 25 men and 19 women. The microbiota is collected using fecal samples. Participants provided these samples during their pre-competitive stage, specifically during the concentration phase occurring two weeks prior to national competitions. This timing is chosen to capture the microbial composition during a period of heightened physical preparation. Questionnaire responses and microbial composition assessments identify disparities among groups. Microbial composition analysis explores core microbiome, abundance, and taxonomy using Pavian, MicrobiomeAnalyst 2.0, and GraPhlAn. ANCOM-BC2 reveals differentially abundant species. Road cyclists exhibit decreased Bacteria and increased Archaea abundance. Phylum-level variations included Planctomycetes, Acidobacteria, and Proteobacteria, while Bacteroidetes prevailed. Key families influencing gut microbiota are Bacteroidaceae, Muribaculaceae, and Selenomonadaceae. Weightlifters exhibit unique viral and archaeal community connections, while cyclists showed specialized microbial interplay influenced by endurance exercise. Correlation network analysis emphasizes distinctive microbial interactions within athlete groups, shedding light on the impact of physical activities on gut microbiota and athlete health.

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This study aimed to investigate the impact of bar velocity during the eccentric phase on subsequent concentric performance in the young and elderly. Twelve elderly women (65.2+4.2 years) and 16 young women (23.1+2.1 years) were randomly assigned to four experimental conditions that combined high-velocity eccentric actions (HVECC; maximum velocity) and moderate-velocity eccentric actions (MVECC; 2.0 s), using 30% and 60% of their 1-repetition maximum (1RM) on the Smith machine bench press. Measurements of mean propulsive velocity (MPV), peak velocity (PV), and mean power (MP) were recorded. Two-way ANOVA with repeated measures was applied for each variable, when needed, the Bonferroni post hoc was used. Statistical significance was set at p<0.05, and effect size (ES) was established by Cohen's d z. The results demonstrated that elderly women showed improved performance in MPV (+10.0%; ES=- 0.58; p=0.009) and MP (+11.7%; ES=- 0.14; p=0.045) when utilizing HVECC at 30% 1RM only. Moreover, young women exhibited superior performance for both 30% and 60% 1RM when using HVECC for all variables analyzed (p<0.05). The HVECC appears to have an impact on the subsequent performance of the concentric phase, particularly when lighter loads (30% 1RM) are utilized, regardless of the age group.

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We compared the effects of resistance training (ResisT) to pyramidal and traditional weightlifting sets on men's psychophysiological responses. In a randomized crossover design, 24 resistance-trained males performed drop-set, descending pyramid, and traditional ResisT in the barbell back squat, 45° leg press, and seated knee extension. We assessed participants' rating of perceived exertion (RPE) and feelings of pleasure/displeasure (FPD) at the end of each set and at 10, 15, 20, and 30 minutes post-session. No differences were detected across ResisT Methods in total training volume (p = 0.180). Post hoc comparisons revealed that drop-set training elicited higher RPE (M 8.8 SD 0.7 arbitrary units) and lower FPD (M -1.4 SD 1.5 arbitrary units) values compared to descending pyramid (M Set RPE 8.0 SD 0.9 arbitrary units and M Set FPD 0.4 SD 1.6 arbitrary units) and traditional set (M Set RPE 7.5 SD 1.1 arbitrary units and M Set FPD 1.3 SD 1.2 arbitrary units) schemes (p < 0.05). In addition, drop-set training elicited higher session RPE (M 8.1 SD 0.8 arbitrary units) and lower session FPD (M 0.2 SD 1.4 arbitrary units) values than descending pyramid and traditional ResisT (p < 0.001). Similarly, descending pyramid training elicited higher session RPE (M 6.6 SD 0.9 arbitrary units) and lower session FPD (M 1.2 SD 1.4 arbitrary units) than traditional set (M Session RPE 5.9 SD 0.8 arbitrary units and M Session FPD 1.5 SD 1.2 arbitrary units) training (p = 0.015). No differences were found in the temporality of post-session metrics, suggesting that testing 10 and 15 minutes post-ResisT was sufficient to assess session RPE (p = 0.480) and session FPD (p = 0.855), respectively. In conclusion, even with similar total training volume, drop-set training elicited more pronounced psychophysiological responses than either pyramidal or traditional ResisT in resistance-trained males.

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This study combined surface electromyography with panoramic ultrasound imaging to investigate whether non-uniform excitation could lead to acute localized variations in cross-sectional area and muscle thickness of the clavicular and sternocostal heads of pectoralis major (PM). Bipolar surface electromyograms (EMGs) were acquired from both PM heads, while 13 men performed four sets of the flat and 45° inclined bench press exercises. Before and immediately after exercise, panoramic ultrasound images were collected transversely to the fibers. Normalized root mean square (RMS) amplitude and variations in the cross-sectional area and muscle thickness were calculated separately for each PM head. For all sets of the inclined bench press, the normalized RMS amplitude was greater for the clavicular head than the sternocostal head (P < 0.001), and the opposite was observed during the flat bench press (P < 0.001). Similarly, while greater increases in cross-sectional area were observed in the clavicular than in the sternocostal head after the inclined bench press (P < 0.001), greater increases were quantified in the sternocostal than in the clavicular head after the flat bench press exercise (P = 0.046). Therefore, our results suggest that the PM regional excitation induced by changes in bench press inclination leads to acute, uneven responses of muscle architecture following the exercise.

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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.

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Background: The application of ischemic preconditioning (IPC) to resistance exercise has attracted some attention, owing to increases in muscle performance. However, there is still no consensus on the optimal occlusion pressure for this procedure. This study compared the acute effects of IPC with high and low pressure of occlusion on upper and lower limb maximal strength and heart rate variability in recreationally trained individuals. Methods: Sixteen recreationally trained men (25.3 ± 1.7 years; 78.4 ± 6.2 kg; 176.9 ± 5.4 cm; 25.1 ± 1.5 m2 kg−1) were thoroughly familiarized with one repetition maximum (1 RM) testing in the following exercises: bench press (BP), front latissimus pull-down (FLPD), and shoulder press (SP) for upper limbs, and leg press 45º (LP45), hack machine (HM), and Smith Squat (SS) for lower limbs. The 1 RM exercises were then randomly performed on three separate days: after a high pressure (220 mmHg, IPChigh) and a low pressure (20 mmHg, IPClow) IPC protocol and after no intervention (control, CON). Heart rate variability was also measured at rest, during and after the entire IPC protocol, and after the exercises. Results: Maximal strength was significantly (p < 0.05) higher in both IPChigh and IPClow compared with CON in all upper- and lower-limb exercises. There was no difference between the two experimental conditions. No significant differences were found in the comparison across the different experimental conditions for LFnu, HFnu, LF/HF ratio, and RMSSDms. Conclusions: IPC performed with both high and low pressures influenced heart rate variability, which may partly explain the maximal strength enhancement.

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INTRODUCCIÓN: La mayoría de los establecimientos educacionales tienen una jornada escolar completa, generando que el estudiante transporte mayor cantidad de útiles escolares en su mochila. OBJETIVO: Analizar el peso promedio de las mochilas de espalda en estudiantes de educación básica de la comuna de Copiapó. METODOLOGÍA: se realizó un estudio descriptivo de corte transversal con alcance correlacional, la muestra estuvo constituida por 286 estudiantes (139 varones y 147 mujeres) de educación básica, de un establecimiento escolar de la comuna de Copiapó. Se analizó el peso corporal, la altura y el peso de las mochilas durante una semana, mediante una plataforma de fuerza y estadiómetro. RESULTADOS: Se encontró que entre los días lunes a jueves los estudiantes llevaban en su mochila un peso que sobrepasaba el 10/ de su peso corporal. Asimismo, las mochilas de espaldas son las más utilizadas en comparación con las mochilas con ruedas, con un 88,1% de la muestra. Sin embargo, las mochilas de espalda presentaron menor peso al compararlas con las mochilas con ruedas, las cuales tuvieron valores cercanos al 20% del peso corporal. CONCLUSIÓN: La mayoría de los estudiantes transportaban en sus mochilas, pesos que superan el 10% de peso recomendado, siendo las mochilas con rueda las de mayor peso. Se recomienda desarrollar normas establecidas dentro de los colegios, para evitar el traslado de dichas cargas y prevenir alteraciones posturales, biomecánicas y fisiológicas.

INTRODUCTION: Most educational establishments have a full school day, causing the student to carry a greater number of school supplies in their backpack. OBJECTIVE: To analyze the average weight of backpacks in basic education students of the Copiapó district. METHODOLOGY: a descriptive cross-sectional study with correlational scope was carried out, the sample consisted of 286 students (139 men and 147 women) of basic education, from a school in the district of Copiapó. Body weight, height and backpack weight were analyzed for one week, using a force platform and stadiometer. RESULTS: It was found that between Monday and Thursday the students carried a weight in their backpack that exceeded 10% of their body weight. Likewise, backpacks on the back are the most used compared to backpacks with wheels, with 88.1% of the sample. However, the backpacks presented less weight when compared to the backpacks with wheels, which had values close to 20% of body weight. CONCLUSION: Most of the students carried weights in their backpacks that exceed 10% of the recommended weight, with wheeled backpacks being the heaviest. It is recommended to develop established norms within the schools, to avoid the transfer of said loads and prevent postural, biomechanical and physiological alterations.

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This study aimed to analyze whether the relationship between regional and whole-body fat-free mass (FFM) and strength is related to FFM distribution and area according to limb involvement. Thirty well-trained male young adults underwent one-repetition maximum test (1RM) to assess the strength in arm curl (AC), bench press (BP), seated row (SR), leg press 45° (LP45), knee extension (KE), and leg curl (LC). Dual-energy X-ray absorptiometry was used to evaluate FFM. The values for 1RM in AC, BP, and R correlated to FFM in upper limb (R2 = 0.69, 0.84 and 0.75), without an effect of appendicular mass index (API) or area. For 1RM in KE, the correlation with FFM in lower limb increased with thigh area (R2 = 0.56), whereas 1RM in LC and LP45 correlation to whole-body FFM increased with API (R2 = 0.64 and 0.49). The upper limb's FFM may be reliable for indexing the arms and upper trunk strengths, whereas the relationships between FFM and strength in lower limb improve as muscle mass and thigh area increases between subjects.

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The bench press is performed in parapowerlifting with the back, shoulders, buttocks, legs and heels extended over the bench, and the use of straps to secure the athlete to the bench is optional. Thus, the study evaluated muscle activation, surface electromyography (sEMG), maximum velocity (MaxV) and mean propulsive velocity (MPV), and power in paralympic powerlifting athletes under conditions tied or untied to the bench. Fifteen experienced Paralympic powerlifting male athletes (22.27 ± 10.30 years, 78.5 ± 21.6 kg) took part in the research. The sEMG measurement was performed in the sternal portion of the pectoralis major (PMES), anterior deltoid (AD), long head of the triceps brachii (TRI) and clavicular portion of the pectoralis major (PMCL). The MaxV, MPV and power were evaluated using an encoder. Loads of 40%, 60%, 80% and 100% 1RM were analyzed under untied and tied conditions. No differences were found in muscle activation between the tied and untied conditions; however, sEMG showed differences in the untied condition between AD and TRI (F (3112) = 4.484; p = 0.005) in the 100% 1RM load, between PMCL and AD (F (3112) = 3.743; p = 0.013) in 60% 1RM load and in the tied condition, between the PMES and the AD (F (3112) = 4.067; p = 0.009). There were differences in MaxV (F (3112) = 213.3; p < 0.001), and MPV (F (3112) = 248.2; p < 0.001), between all loads in the tied and untied condition. In power, the load of 100% 1RM differed from all other relative loads (F (3112) = 36.54; p < 0.001) in both conditions. The tied condition seems to favor muscle activation, sEMG, and velocity over the untied condition.

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ABSTRACT: Rodrigues, GM, Machado, S, Faria Vieira, LA, Ramalho de Oliveira, BR, Jesus Abreu, MA, Marquez, G, Maranhão Neto, GA, and Lattari, E. Effects of anodal transcranial direct current stimulation on training volume and pleasure responses in the back squat exercise following a bench press. J Strength Cond Res 36(11): 3048-3055, 2022-This study aimed to investigate the effects of anodal transcranial direct current stimulation (a-tDCS) on volume-load and pleasure responses in a back squat following a bench press. Twelve male subjects advanced in resistance training (RT) (age, 25.5 ± 4.4 years) completed 2 experimental trials in a counterbalanced crossover design: a-tDCS and sham conditions. The stimulus was applied over the left dorsolateral prefrontal cortex for 20 minutes using a 2-mA current intensity in a-tDCS condition and 1 minute of active stimulus in the sham condition. Immediately after stimulation, subjects performed the bench press followed by the back squat. The exercise protocol consisted of 3 sets of maximum repetitions at an intensity of 80% of 1 repetition maximum. The volume-load, perceived pleasure, and arousal responses were measured during the RT protocol. The results indicated that volume-load was higher in the a-tDCS condition than in the sham condition for both exercises ( p = 0.02), with large effect for the back squat ( p = 0.045; d = 0.96). The higher volume-load was obtained by increasing the number of repetitions across all sets for the bench press ( p ≤ 0.0001) and only in the first set for the back squat ( p = 0.01). The circumplex model analysis showed a higher pleasure in the bench press and a tendency toward a higher pleasure in the a-tDCS condition. Anodal tDCS may be used as an ergogenic resource for increasing the back squat volume after performing the bench press in resistance-trained male subjects.

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ABSTRACT: Dos Santos, WM, Tavares Junior, AC, Braz, TV, Lopes, CR, Brigatto, FA, and Dos Santos, JW. Resistance-trained individuals can underestimate the intensity of the resistance training session: An analysis among genders, training experience, and exercises. J Strength Cond Res 36(6): 1506-1510, 2022-Resistance training (RT) promotes improvements in healthy parameters for young to elderly adults and athletes' performance. Strength and muscle mass improvements are dependent on exercise intensity. This study verifies whether 53 healthy young adults underestimate exercise intensity in 3 different exercises, such as bench press (BP), biceps curl (BC), and leg press 45° (LP). Researchers asked the subjects "How much load do you use to perform 10 repetitions in this exercise usually in workout routines?" in each exercise. Individuals warmed up and then performed as many repetitions as possible until they reached the concentric failure. Deviations from data normality were found by using Levene's test; the number of repetitions per exercise within sex was tested by using Friedman's test and Conover's post hoc and Kruskal-Wallis tests to compare the number of repetitions between sex and RT experience. We correlated the number of repetitions and training experience using the Spearman test. The number of repetitions for both groups (male and female) is greater than 8-12 repetitions for BC and LP and BP of the female group, except for men who perform around 8-12 repetitions on BP. Frequency of maximal repetitions reached for 8-12 repetitions for women was 12% for BP, 28% for BC, and 28% for LP. The frequency men reached was 46.5% for BP, 14.3% for BC, and 14.3% for LP. Training experience did not influence the number of repetitions reached. Resistance training practitioners underestimate exercise load (56% of total sample) to be independent of experience. Women underestimate exercise load more than men. Based on the present results, it is possible to state that RT should not be prescribed considering a predefined number of repetitions and a linked percentage of loads, without the guidance for frequent adjustments of loads, according to the exercise performed.

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ABSTRACT: Medeiros, LHL, Sandbakk, SB, Bertazone, TMA, and Bueno Júnior, CR. Comparison of periodization models of concurrent training in recreationally active postmenopausal women. J Strength Cond Res 36(4): 977-983, 2022-Although concurrent training is the most effective way to improve both neuromuscular and cardiorespiratory functions in older populations, there are no studies in the literature comparing different periodization models on cardiorespiratory and muscle strength adaptations. Thus, the main objective of this study was to investigate the effects of different periodization models of concurrent aerobic and strength training using equalized training volume programs on muscle strength and cardiorespiratory fitness in recreationally active postmenopausal women. After 3 weeks of adaptation, 58 women aged 50-75 years were randomly assigned to (a) nonperiodization (NP), (b) daily nonlinear periodization (NLP), or (c) flexible daily NLP (FNLP). At baseline and after 12 weeks, aerobic fitness (peak oxygen uptake [V̇o2peak] and the 6-minute walk test) and maximal muscle strength (1 repetition maximum of bench press and leg press) were measured. It was shown that maximal strength increased in the bench press (effect size [ES] 1.18 in NLP and 1.22 in FNLP) and leg press (ES 0.92 in NLP and 0.89 in FNLP) in the periodized groups-in the NP group, these values were 0.49 and 0.46, respectively. In the 6-minute walk test, aerobic fitness statistically improved in all groups-with an ES of 1.02 in the NP, 1.33 in the NLP, and 0.54 in the FNLP. This study showed that only periodization models (NLP and FNLP) induced a moderate ES in maximal strength, and all groups (NP, NLP, and FNLP) demonstrated improved aerobic fitness evaluated by V̇o2peak and the 6-minute walk test in recreationally active postmenopausal women.

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Bodybuilding involves athletes performing a series of poses/postures on the stage so that they can be classified according to their best esthetic and physical appearance during the competition. In the weeks prior to the target competition, the athletes subject themselves to restrictive diets and different physical training methods, as well as using dietary supplementation and, in some cases, anabolic steroids, to reduce body fat to low levels and maintain or increase muscle mass. On the other hand, it is known that physical training is a potent stimulator for releasing the components of the GH/IGF-I axis that are directly linked to the anabolic process. Based on these assumptions, this study aimed to verify the kinetics of IGF-I and of its binding protein IGFBP-3 in female bodybuilders. Serum IGF-I and IGFBP-3 concentrations were recorded before and after standardized training sessions at two different times: in the initial phase (phase 1) and in the final phase of the pre-contest (phase 2) of a 12-week training season. It was possible to conclude that there was a significant reduction in serum IGF-I values at the end of the pre-contest phase that preceded the athletes' participation in a competition. With relation to the serum IGF-I and IGFBP-3 values measured before and after the standardized training session, it was only possible to verify significant changes in the IGF-I values in the initial phase of the pre-contest. It seems reasonable to suggest that the caloric restriction used by bodybuilders may be related to the decrease in IGF-I values verified at the end of the pre-contest phase.

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External load influences internal load in resistance training (RT). The purpose of the present study was to compare the total volume-load, perceptual and stress responses during three different RT protocols. Twelve resistance-trained men completed three different RT protocols with the back squat and bench press exercises: (1) power (POW) (5 sets of 6 repetitions at 50%1RM, 2-min of rest), (2) hypertrophy (HYP) (5 sets-to-failure at 75%1RM, 2-min of rest), and (3) strength (STR) (5 sets-to-failure at 90%1RM, 3-min of rest). Volume-load (kg × reps.), session rating of perceived exertion (sRPE), training impulse (TRIMP; reps. × sRPE), cortisol, immunoglobulin A (IgA), lactate, and creatine kinase (CK) were assessed before and/or after the sessions. HYP was the most demanding session in terms of volume-load (p < 0.001), TRIMP (p < 0.001), cortisol (p = 0.001), lactate (p < 0.001), and CK (p = 0.001). Despite POW exhibited a greater volume-load than STR (p = 0.016), the latter exhibiting a greater sRPE (p < 0.001), and a greater post-session CK (p = 0.05). However, the TRIMP of STR and POW were not statistically different (152 vs. 260 AU; p = 0.089). These specific responses could be meditated by the presence of muscular failure. When pooling all the sessions, significant correlations were revealed among external and internal stress markers (r = 0.35-0.80; p ≤ 0.05). The use of TRIMP could be recommended as a simple and valid monitoring tool which integrates into a single parameter the internal and the external loads of RT sessions.

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ABSTRACT: da Silva Novaes, J, da Silva Telles, LG, Monteiro, ER, da Silva Araujo, G, Vingren, JL, Silva Panza, P, Reis, VM, Laterza, MC, and Vianna, JM. Ischemic preconditioning improves resistance training session performance. J Strength Cond Res 35(11): 2993-2998, 2021-The aim of this study was to investigate the acute effect of ischemic preconditioning (IPC) in a resistance exercise (RE) training session on the number of repetitions performed, total volume, and rating of perceived exertion in recreationally trained and normotensive men. Sixteen recreationally trained and normotensive men completed 3 RE sessions in a counterbalanced and randomized order: (a) IPC protocol using 220 mm Hg followed by RE (IPC), (b) IPC cuff control protocol with 20 mm Hg followed by RE (CUFF), and (c) no IPC (control) followed by RE (CON). RE was performed with 3 sets of each exercise (bench press, leg press, lateral pulldown, hack machine squat, shoulder press, and Smith back squat) until concentric muscular failure, at 80% of one repetition maximum, with 90 seconds of rest between sets and 2 minutes of rest between exercises. Ischemic preconditioning and CUFF consisted of 4 cycles of 5 minutes of occlusion/low pressure alternating with 5 minutes of no occlusion (0 mm Hg) using a pneumatic tourniquet applied around the subaxillary region of the upper arm. For each condition, the number of repetitions completed, total volume of work performed, and rating of perceived exertion were determined. No significant difference was found for rating of perceived exertion between any experimental protocol. Ischemic preconditioning significantly (p < 0.05) increased the number of repetitions across exercises. Consequently, total volume performed (sum of total number of repetitions x load for each exercise) was significantly higher in IPC (46,170 kg) compared with CON (34,069 kg) and CUFF (36,590 kg) across all exercises. This work may have important implications for athletic populations because it demonstrates increase in muscle performance outcomes during a single RE session. Therefore, performing IPC before RE could be an important exercise prescription recommendation to increase maximum repetition performance and total volume of work performed and thus potentially increase desired training adaptations (i.e., strength and hypertrophy).

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