Strength-trained Men Research Articles

Load-Velocity Relationship in the Bulgarian Split-Squat Exercise.

Rabal-Pelay, J, Gutiérrez, H, Bascuas, P-J, Pareja-Blanco, F, and Marco-Contreras, LA. Load-velocity relationship in the Bulgarian split-squat exercise. J Strength Cond Res XX(X): 000-000, 2024-The objective of the current research was to analyze the load-velocity relationship in the Bulgarian split-squat (BSS) exercise and to compare these relationships between the dominant and nondominant legs. Twenty-one strength-trained men (age: 27.3 ± 7.3 years) performed a progressive loading test in the BSS exercise using a Smith machine for each leg. The protocol began with a load of 30 kg, incrementally adding 10 kg until the mean propulsive velocity (MPV) fell below 0.4 m·s-1. At that point, 5 kg increments were employed, with a final addition of 2.5 kg for the last estimated attempt one-repetition maximum (1RM). A total of 324 lifts were analyzed. Subjects exhibited a relative strength ratio of 1.23 ± 0.10, a 1RM of 91.3 ± 14.2 kg, and a mean range of motion of 44.7 ± 3.7 cm. Polynomial regression analysis showed a robust relationship with an R2 value of 0.945 (ρ ≤ 0.001) between the relative load (%1RM) and MPV. Despite the differences in 1RM between the dominant and nondominant legs, there were no significant differences in MPV at the %1RM between both legs. These findings suggest that training intensity can be prescribed via the MPV during the BSS exercise. Moreover, the load-velocity relationship is stable between limbs despite the potential differences in absolute strength levels.

Acute Responses to Different Velocity Loss Thresholds during Squat Exercise with Blood-Flow Restriction in Strength-Trained Men.

(1) Background: The aim of this paper is to analyze the acute effects of different velocity loss (VL) thresholds during a full squat (SQ) with blood-flow restriction (BFR) on strength performance, neuromuscular activity, metabolic response, and muscle contractile properties. (2) Methods: Twenty strength-trained men performed four protocols that differed in the VL achieved within the set (BFR0: 0% VL; BFR10: 10% VL; BFR20: 20% VL; and BFR40: 40% VL). The relative intensity (60% 1RM), recovery between sets (2 min), number of sets (3), and level of BFR (50% of arterial occlusion pressure) were matched between protocols. Tensiomyography (TMG), blood lactate, countermovement jump (CMJ), maximal voluntary isometric SQ contraction (MVIC), and performance with the absolute load required to achieve 1 m·s-1 at baseline measurements in SQ were assessed before and after the protocols. (3) Results: BFR40 resulted in higher EMG alterations during and after exercise than the other protocols (p < 0.05). BFR40 also induced greater impairments in TMG-derived variables and BFR10 decreased contraction time. Higher blood lactate concentrations were found as the VL within the set increased. BFR0 and BFR10 showed significantly increased median frequencies in post-exercise MVIC. (4) Conclusions: High VL thresholds (BFR40) accentuated metabolic and neuromuscular stress, and produced increased alterations in muscles' mechanical properties. Low VL could potentiate post-exercise neuromuscular activity and muscle contractile properties.

Identification of Peripheral Fatigue through Exercise-Induced Changes in Muscle Contractility.

The aim of this study was to assess whether tensiomyography is a tool sensitive enough to detect peripheral fatigue. Twenty-six strength-trained men were split into two groups: 1) a fatigued group (FG), who performed a full-squat (SQ) standardized warm-up plus 3 x 8 SQs with 75% 1RM with a 5-min rest interval, and 2) a non-fatigued group (NFG), who only did the SQ standardized warm-up. The countermovement jump (CMJ), maximal isometric force (MIF) in the SQ at 90º knee flexion, and TMG in vastus medialis (VM) and vastus lateralis (VL) muscles were assessed pre- and post-protocols. Data were analyzed through mixed ANOVA, logistic regression analysis, and receiver-operating curves. There were significant group x time interactions (p < 0.01) for CMJ height, MIF, maximal radial displacement (Dm), and radial displacement velocity (Vrd90) since the FG acutely decreased in these variables, while no significant changes were observed for the NFG. The logistic regression showed a significant model for detecting fatigue, whether it used the CMJ or MIF, with only the relative change in VL-Vrd90 as a fatigue predictor. The determination of the area under the curve showed that Dm and Vrd90 had good to excellent discriminative ability. Dm and Vrd90 are sensitive to detect fatigue in VL and VM muscles in resistance training contexts.

Platelet activity, coagulation, and fibrinolysis in long-term users of anabolic-androgenic steroids compared to strength-trained athletes

IntroductionUse of anabolic-androgenic steroids (AAS) is associated with adverse cardiovascular (CV) effects, including potential prothrombotic effects. This study aimed to assess platelet activation and aggregation, coagulation, and fibrinolysis, in long-term AAS users compared to non-using strength-trained athletes. Materials and methodsThirty-seven strength-trained men using AAS were compared to seventeen non-using professional strength-trained athletes at similar age (median 33 years). AAS use was verified by blood and urine analyses. Platelet Function Analyzer 100 (PFA-100) and whole blood impedance aggregometry with thrombin, arachidonic acid, and ADP as agonists, were performed to evaluate platelet aggregation. ELISA methods were used for markers of platelet activation. Fibrinogen, D-dimer, the coagulation inhibitors protein S and C activity, and antithrombin were measured by routine. Fibrinolysis was evaluated by Plasminogen Activator Inhibitor-1 (PAI-1) activity. ResultsThere were no significant differences in platelet aggregation between the two groups. Von Willebrand factor was lower among the AAS users (p < 0.01), and P-Selectin was slightly higher (p = 0.05), whereas CD40 Ligand, β-thromboglobulin, and thrombospondin did not differ significantly. No differences were found in the assessed coagulation inhibitors. Higher D-dimer levels (p < 0.01) and lower PAI-1 activity (p < 0.01) were found among the AAS users. ConclusionsThe investigated long-term users of AAS did not exhibit elevated platelet activity compared to strength-trained non-using athletes. However, AAS use was associated with higher D-dimer levels and lower PAI-1 activity. These findings suggest that any prothrombotic effect of long-term AAS use may predominantly involve other aspects of the hemostatic system than blood platelets.

Circulating catecholamines, endothelin-1, and nitric oxide releases do not explain the preserved FMD following acute resistance exercise in strength-trained men.

Acute resistance exercise decreases endothelial function in sedentary individuals but not in strength-trained (ST) individuals. However, the underlying mechanism(s) of vascular protection in ST individuals remains unclear. Herein, we compared catecholamines, endothelin-1 (ET-1), and nitric oxide (NOx) releases after acute resistance exercise between sedentary and ST individuals. The untrained (UT) group comprised 12 male individuals with no regular training, while the ST group comprised 12 male individuals. Participants performed a session of resistance exercise, which consisted of 3 sets of 10 repetitions at 75% of one repetition maximum. Heart rate (HR) and blood pressure were measured during resistance exercise. Brachial artery flow-mediated dilation (FMD), blood pressure, HR, and blood collection were undertaken before and 10, 30, and 60 min after the resistance exercise. No significant difference was found in baseline brachial artery FMD between the groups (P > 0.05). Brachial artery FMD was significantly reduced in the UT group (P < 0.05) but it was prevented in the ST group after the resistance exercise. Significant differences were found at 10, 30, and 60 min after the resistance exercise in brachial artery ΔFMD from baseline between groups (P < 0.05). Blood pressure, HR, plasma epinephrine, norepinephrine, dopamine, serum endothelin-1, and plasma NOx responses did not differ between groups throughout the experimental period. In conclusion, preserved endothelial function in response to acute resistance exercise in ST male individuals is independent of catecholamines, ET-1, and NOx responses.

Non-Local Muscle Fatigue Impairs Mean Propulsive Velocity During Strength Loading in Strength-Trained Men

ABSTRACT Purpose: This study examined the acute influence of a bench press (BP) loading on the explosive squat (SQ) performance and vice versa. Methods: Nineteen strength-trained men completed 2 experimental sessions consisting of either a SQ+BP loading or a BP+SQ loading with 3 × 5 + 3 × 3 repetitions at 80% of the 1-repetition maximum in a randomized order. SQ and BP mean propulsive velocity (MPV) were assessed during both loadings, at baseline (T0) as well as immediately after the first (T1) and second strength loading (T2). Results: Both BP and SQ MPV decreased between T0 and T1 in SQ+BP (−6.13 ± 6.13%, p = .014, g = 0.485 and −9.11 ± 7.23%, p < .001, g = 0.905, respectively) and BP+SQ (−15.15 ± 7.69%, p < .001, g = 1.316 and −7.18 ± 6.16%, p < .001, g = 0.724, respectively). Mean BP MPV was lower in set 2 to set 6 in SQ+BP when compared to BP+SQ (−7.90% − 9.88%, all p < .05, g = 0.523–0.808). Mean SQ MPV was lower in set 1 and set 4 in BP+SQ when compared to SQ+BP (−4.94% − 5.22%, all p < .001, g = 0.329–0.362). Conclusions: These results demonstrate that the presence of non-local muscle fatigue affects the movement velocity. Therefore, if a training program aims to perform strength training exercises with maximal movement velocity, it is essential to carefully evaluate whether upper and lower body exercises should be carried out within close proximity.

Comparison of kinematics and electromyography in the last repetition during different maximum repetition sets in the barbell back squat.

The barbell squat is an exercise used to strengthen the lower limbs, with implications for both performance in sports and improving movement during everyday tasks. Although the exercise is being trained across a variety of repetition ranges, the technical requirements may vary, affecting appropriate repetition range for specific training goals. A randomised within-subject design was used to compare kinematics and surface electromyography (EMG) in the lower extremities during different concentric phases (pre-, sticking- and post-sticking region) of the last repetition when performing squats at different repetition maximums (RMs). Thirteen strength-trained men (age: 23.6 ± 1.9 years; height: 181.1 ± 6.5 cm; body mass: 82.2 kg, 1RM: 122.8 ± 16.2, relative strength: 1.5 ± 0.2 x body mass in external load) performed a 1, 3, 6, and 10RM squat, in a randomised order. The main findings were that barbell-, ankle-, knee- and hip kinematics were similar across different repetition ranges, except for a smaller trunk lean at 1RM in the pre-sticking region compared to other repetitions and in the sticking region compared to 10RM (p ≤ 0.04). Furthermore, 1RM revealed significantly higher EMG amplitude in the vastus lateralis, gastrocnemius and soleus in the sticking and post-sticking regions when compared to 10RM. It was concluded that 10RM may locally fatigue the vastus lateralis and plantar flexors, explaining the lower EMG amplitude. The observed differences indicate that requirements vary for completing the final repetition of the 10RM compared to the 1RM, an important aspect to consider in training to enhance 1RM strength.

Evaluation of the Vmaxpro sensor for assessing movement velocity and load-velocity variables: accuracy and implications for practical use.

We investigated the ecological validity of an inertial measurement unit (IMU) (Vmaxpro) to assess the movement velocity (MV) during a 1-repetition maximum (1RM) test and for the prediction of load-velocity (L-V) variables, as well as the ecological intra- day and inter-day reliability during free-weight bench press (BP) and squat (SQ). Furthermore, we provide recommendations for the practical use of the sensor. Twenty-three strength-trained men completed an incremental 1RM test, whereas seventeen men further participated in another 3 sessions consisting of 3 repetitions with 4 different loads (30, 50, 70 and 90% of 1RM) to assess validity and intra- and inter-day reliability, respectively. The MV was assessed using the Vmaxpro and a 3D motion capture system (MoCap). L-V variables and the 1RM were calculated based on submaximal velocities. The Vmaxpro showed high validity during the 1RM test for BP (r = 0.935) and SQ (r = 0.900), but with decreasing validity at lower MVs. The L-V variables and the 1RM demonstrated high validity for BP (r = 0.808-0.942) and SQ (r = 0.615-0.741) with a systematic overestimation. Coefficients of variance for intra- and inter-day reliability ranged from 2.4% to 9.7% and from 3.2% to 8.6% for BP and SQ, respectively. The Vmaxpro appears valid at high and moderately valid at low MVs. Depending on the required degree of accuracy, the sensor may be sufficient for the prediction of L-V variables and the 1RM. Our data indicate the sensor to be suitable for monitoring changes in MVs within and between training sessions.

Short term creatine loading improves strength endurance even without changing maximal strength, RPE, fatigue index, blood lactate, and mode state.

Creatine is consumed by athletes to increase strength and gain muscle. The aim of this study was to evaluate the effects of creatine supplementation on maximal strength and strength endurance. Twelve strength-trained men (25.2 ± 3.4 years) supplemented with 20 g Creatina + 10g maltodextrin or placebo (20g starch + 10g maltodextrin) for five days in randomized order. Maximal strength and strength endurance (4 sets 70% 1RM until concentric failure) were determined in the bench press. In addition, blood lactate, rate of perceived effort, fatigue index, and mood state were evaluated. All measurements were performed before and after the supplementation period. There were no significant changing in maximal strength, blood lactate, RPE, fatigue index, and mood state in either treatment. However, the creatine group performed more repetitions after the supplementation (Cr: Δ = +3.4 reps, p = 0.036, g = 0.53; PLA: Δ = +0.3reps, p = 0.414, g = 0.06), and higher total work (Cr: Δ = +199.5au, p = 0.038, g = 0.52; PLA: Δ = +26.7au, p = 0.402, g = 0.07). Creatine loading for five days allowed the subjects to perform more repetitions, resulting in greater total work, but failed to change the maximum strength.

Sprint Cycling

Abstract: The time between races varies in the track cycling competition known as the Match Sprint but can be as little as 10–15 min. Both physiological and motivational factors could affect performance recovery. This study investigated how the between-sprint recovery activity, and an alteration in the duration of the second sprint, affected performance. Twenty-four strength-trained men (age: 26 ± 5 years; height: 180.3 ± 6.1 cm; body mass: 82.3 ± 6.9 kg) participated. During each of the four experimental trials, two sprints were performed 12 min apart. The first was always 18 s and the second was either 9 s or 18 s. Between sprints, passive rest or a mixture of active and passive recovery was undertaken. Peak power output (PPO), as well as mean power output over 9 s (MPO9) and 18 s (MPO18), was recorded. Lactate concentration, ratings of sprint preparation and performance, as well as perceptions of recovery, were also measured. Post-trial and post-study questionnaires explored factors that may have influenced performance. A sprint number × recovery method interaction, F(1, 23) = 28.791, p &lt; .001, ηp2 = .556, was found for PPO, with a significantly lower PPO in sprint 2 following passive recovery. Sprint number × second sprint duration interactions were found for PPO, F(1, 23) = 9.867, p = .005, ηp2 = .300, and MPO9, F(1, 23) = 8.922, p = .007, ηp2 = .279. A significant time × condition interaction was also found for lactate concentration, F(6.082, 97.320) = 2.982, p = .010, ηp2 = .157, although post hoc tests were unable to identify the cause of any of these effects. Typically, the participants were satisfied with their sprint performances and expressed positive views about the recovery activity undertaken. The main finding was, therefore, that PPO was lower following passive recovery, but the effects on MPO were not apparent.

A Biomechanical Comparison between Squatbar® and Olympic Barbell

When performing the traditional barbell back squat, athletes may experience discomfort in the shoulders or be limited by shoulder mobility. The Squatbar® is a barbell designed to be ergonomic to the shoulders but has never, in the scientific literature, been compared to the traditional Olympic barbell. Thus, the current study investigated kinematics, kinetics, and myoelectric activity (EMG) between the Squatbar® barbell and the Olympic barbell when performing a one-repetition maximum (1-RM) back squat. Twelve strength-trained men (body mass: 83.5 ± 7.8 kg, age: 27.3 ± 3.8 years, height: 180.3 ± 6.7 cm) performed a 1-RM squat with both the Olympic and Squatbar® barbells. The paired samples t-test revealed significantly more weight was lifted with the Olympic barbell compared to the Squatbar® barbell (148 ± 21 kg vs. 144.5 ± 20 kg) and was accompanied by greater shoulder external rotation (74 ± 7.5° vs. 59.6 ± 9.2°). No differences in joint kinematics of the lower limbs, kinetics, or EMG were observed between the two barbells. The results of the current study indicate the Squatbar® to be a suitable substitution for the Olympic barbell for athletes with reduced shoulder mobility when performing the squat. It was concluded that the Squatbar® induces similar kinetics, kinematics, and EMG when compared to the Olympic barbell, except for reducing external rotation of the shoulder.

Upper-lower body super-sets vs. traditional sets for inducing chronic athletic performance improvements.

To promote chronic adaptations, resistance training needs the manipulation of different variables, among them, the order of the exercises and sets. Specifically, for velocity-based training, paired exercises alternating upper and/or lower-body muscle groups appear to be a good choice to promote neuromuscular adaptations. This study aimed to compare the effect of two velocity-based training programs only differing in the set configuration on muscle strength, muscular endurance and jump performance. Moderately strength-trained men were allocated into a traditional (TS, n= 8) or alternating sets (AS, n= 9) configuration group to perform a 6-week velocity-based training program using the full squat (SQ) and bench press (BP) exercises. The TS group completed all sets of the full squat (SQ) exercise before performing the bench press (BP) sets, whereas the AS group completed the first set of each exercise in an alternating manner. Training frequency, relative load, number of sets, percentage of velocity loss (%VL) within the set and inter-set rest were matched for both groups. Countermovement jump height (CMJ), load (kg)-velocity relationship, predicted 1RM, and muscular endurance for each exercise were evaluated at pre- and post-training. The TS and AS groups obtained similar and non-significant improvements in CMJ (3.01 ±4.84% and 3.77 ±6.12%, respectively). Both groups exhibited significant and similar increases in muscle strength variables in SQ (6.19-11.55% vs. 6.90-011.76%; p=0.033-0.044, for TS and AS, respectively), BP (6.19-13.87% and 3.99-9.58%; p=0.036-0.049, for TS and AS group, respectively), and muscular endurance in BP (7.29 ±7.76% and 7.72 ±9.73%; p=0.033, for the TS and AS group, respectively). However, the AS group showed a greater improvement in muscular endurance in SQ than the TS group (10.19 ±15.23% vs. 2.76 ±7.39%; p=0.047, respectively). Total training time per session was significantly shorter (p=0.000) for AS compared to TS group. Training programs performing AS between SQ and BP exercises with moderate loads and %VL induce similar jump and strength improvements, but in a more time-efficient manner, than the traditional approach.

The Effect of Unilateral Versus Bilateral Strength Training on Isometric-Squat Peak Force and Interlimb Asymmetry in Young, Recreationally Strength-Trained Men.

To compare the effects of bilateral strength training (BLST) versus unilateral strength training (ULST) on changes in peak force (PF) and interlimb asymmetry (ILA) in the isometric squat at a 120° knee angle (ISq120). A total of 31 young, recreationally strength-trained men performed either BLST (n = 18) or ULST (n = 13), twice per week for 6weeks. The total number of repetitions, duty cycle, and effort were standardized between training groups (ie,differing only in the exercises performed). Changes in PF and ILA were assessed pretraining and posttraining. Comparable increases in PF were observed in the BLST group (mean [SD] change; 17.4% [20.5%], P = .001, standardized mean difference [SMD] = 0.45) and the ULST group (11.4% [19.1%], P = .042, SMD = 0.25). No significant changes in symmetry index (SI) scores were observed following BLST (mean [SD] change; 0 [5.7], P = .526, SMD = -0.12) or ULST (+3 [6.0], P = .702, SMD = 0.4). Individual analyses of subjects with marked ILA (ie,baseline SI score > baseline coefficient of variation) revealed a trend toward BLST being more effective at attenuating SI scores in the ISq120. Overall, both BLST and ULST are effective for increasing ISq120 PF. However, it appears that BLST may be more effective at reducing SI scores in those with marked ILA.

Efeitos do treinamento de força em dias consecutivos e não consecutivos nas respostas hormonal, neuromuscular e morfológica em homens treinados recreacionalmente

abstract The purpose of the present study was to investigate the effect of two recovery periods between consecutive and non-consecutive days in strength training sessions on hormonal, neuromuscular and morphological variables in recreationally trained men. Nineteen young men completed the study and were randomly divided into two groups: 24R, 24-hour recovery group (n = nine) and 72R, 72-hour recovery group (n = ten). The strength training program (RT) lasted six weeks with two serial routines, with a weekly frequency of four times. The saliva sample was collected once a week in the morning to determine salivary testosterone. The 1RM, jump against movement and body composition tests were performed in the pre- and post-training periods. As for salivary testosterone, there was no significant effect with respect to time and between groups. Both groups improved maximal strength in terms of intervention time in the barbell bench press and in the leg press 45º, not differing between groups and body composition showed significant interaction in time to body fat percentage ∆% = -14.6 ± 10.0 (24R) and -17.2 ± 10.9 (72R); p = 0.00, fat mass ∆% = -13, 7 ± 9.2 (24R) and -18.2 ± 13.0 (72R); p = 0.00 and fat-free mass ∆% = 3.5 ± 2.7 (24R) and 2.5 ± 2 .8 (72R), p = 0.00. The recovery periods 24 and 72 hours between sessions induced similar responses in the parameters investigated in recreationally strength-trained men.

The short-term recovery of sprint cycling performance

Short-term sprint cycling performance recovery was investigated, with consideration to the Match Sprint. Fifteen strength-trained men (age: 24 ± 6 years; height: 1.81 ± 0.08 m; body mass: 83.4 ± 8.4 kg) were first familiarised with an 18 s sprint. During the baseline trial, blood lactate concentration, tissue saturation index, and oxygen uptake were monitored following a single sprint. In the remaining trials, the recovery duration (45, 90, 135, 180, 360, and 720 s) between two sprints was varied. Peak (PPO) and mean (MPO) power output were computed for each sprint. The recovery percentage of MPO and the recovery time-course of the physiological variables were modelled using one- and two-phase exponential functions. Statistical significance was set a priori at p &lt; 0.05. Effects of sprint number, recovery time, and a sprint number × recovery time interaction were found for both PPO and MPO. Post hoc tests revealed significant differences between sprints at all time-points for both variables. The time constant (τ), 130.6 ± 95.6 s, of the one-phase exponential function (asymptotic amplitude [A0] = 97.4 ± 2.5%), suggested that performance recovery had stabilised within 12 minutes. However, the parameters of the two-phase function indicated that recovery was incomplete (A0 = 87.7 ± 6.4%, A1 = 11.9 ± 5.2%, τ0 = 56.3 ± 33.3 s, τ1 = 458.2 ± 283.3 s). The τ for MPO recovery was not significantly correlated with any of the physiological variables. The reduction in sprint cycling performance throughout the tested time-period could be meaningful for athletes competing in the Match Sprint.

Effect of attentional focus on squats on lactate production and rating of perceived exertion in trained men

The aim of this study was to investigate the effect of internal focus (IF) and external focus (EF) on lactate production and the perception of perceived exertion in the squat in strength trained-men. Methods: Thirteen men with experience in strength training (age =22.61 ± 1.19 years; height = 180 ± 6.55 cm; body mass = 79.38 ± 5.57 kg; BMI = 24.56 ± 2.11 kg·m-2; Squat = 129 ± 20 kg) performed two sessions, separated by one week, comprising 3 sets of 10 repetitions of the back squat with one minute of rest between sets. During the IF protocol participants were instructed to focus on tightening the quads during all repetitions, while participants in the EF were instructed to focus on lifting the barbell. Blood lactate samples were collected before and at immediately after each of the 3 sets, as well as 15 minutes after the last set. Additionally, the rating of perceived exertion (RPE) was evaluated using the OMNI-RES scale immediately after the completion of each session. Results: Significant increases were found in the IF protocol at the end of each of the 3 sets, with significant effect sizes (1ª set, P= .000, d= 2.66; 2ª set, P= .000; d= 3.14; 3ª set, P= .000, d= 3.50), as in the EF protocol (1ª set, P= .001, d= 2.24; 2ª set, P= .000, d= 3.35; 3ª set, P= .000; d= 3.67). However, there were no significant inter-group differences between pre and any set (1ª set, P=0.951, d=0.03; 2ª set, P=0.239, d=0.47; 3ª set, P=0.435, d=0.31, respectively). Additionally, the perceptions on the RPE scale were higher in the FI (P= 0.032; d = 0.47). Conclusions: Findings suggest that the application of IF may indirectly contribute to muscle hypertrophy in multi-joint lower limb exercises, due to the increase in RPE values and the existing correlation with lactate production. Keywords: Mind-muscle, muscle hypertrophy, internal focus, mind-muscle connection, resistance training

MRI Characterization Of Skeletal Muscle Size And Fatty Infiltration In Long-term Trained And Untrained Individuals

PURPOSE: We aimed to investigate various body composition measures in highly trained and untrained men and women using whole-body magnetic resonance imaging (MRI). Additionally, correlations between these measures and skeletal muscle gene expression were performed. METHODS: Thirty-six individuals were included: endurance-trained men (ME, n = 8) and women (FE, n = 7), strength-trained men (MS, n = 7) or untrained control men (MC, n = 8) and women (FC, n = 6). Whole-body MRI scans were performed, and m. vastus lateralis biopsies were collected at rest. Cross-sectional area (CSA) and infiltration of muscular adipose tissue (IMAT) were calculated from Mm. pectoralis, M. erector spinae and M. multifidus combined, Mm. quadriceps, and Mm. triceps surae (TS). RESULTS: ME and FE had significantly lower liver fat fraction, visceral fat volume and total body fat mass relative to body weight than MC and FC, respectively. MS had larger CSA across all four muscle groups and less IMAT in all muscles apart from TS (p = 0.053) compared with MC. ME was found to have less IMAT across all muscle groups and a larger CSA in three of the four muscle groups compared with MC. However, the only difference in IMAT between FE and FC was found in Mm. pectoralis. Functional analysis of muscle gene expression of the top 50 genes that correlated most strongly with IMAT revealed a significant enrichment of the AMPK-pathway. CONCLUSIONS: This study suggests that both regular endurance and resistance training are, over time, appropriate to maintain muscle mass and reduced skeletal muscle infiltration of adipose tissue in male adults. Although a significant relationship between IMAT and the AMPK pathway was found, future studies are needed to determine the mechanism by which infiltration of adipose tissue is regulated in muscle.

Acute Effect of Upper-Lower Body Super-Set vs. Traditional-Set Configurations on Bar Execution Velocity and Volume.

This study aimed to compare the effect on bar execution velocity and number of repetitions between two velocity-based resistance training protocols only differing in the set configuration of the full-squat (SQ) and bench-press (BP) exercises. Moderately strength-trained men were assigned to a traditional (TS, n = 9)- or an alternating-set (AS, n = 10) configuration group to perform four testing sessions against different relative loads (55–60–65–70% 1RM). Relative load, magnitude of intra-set velocity loss (%VL), number of sets, inter-set recovery time, and exercise order were matched for both groups in each session. Mean propulsive velocity of the first repetition (MPVfirst), average number of repetitions per set (NRS), total number of repetitions (TNR), and total training time per session (TT) were measured. No significant differences between training conditions were observed for any relative load in MPVfirst, NRS, and TNR in both exercises. The TS group completed a significantly higher number of repetitions (p < 0.05) at faster velocities (MPV > 0.9–1.1 m·s−1) in the SQ. In conclusion, training sessions performing AS between SQ and BP exercises with moderate relative loads and %VL result in similar bar execution velocity and volume, but in a more time-efficient manner, than the traditional approach.

Range of Motion Predicts Performance in National-Level New Zealand Male Powerlifters.

Spence, AJ, Helms, ER, Sousa, CA, and McGuigan, MR. Range of motion predicts performance in National-level New Zealand male powerlifters. J Strength Cond Res 37(1): 123-128, 2023-Previous research established that male powerlifters have less range of motion (ROM) in several movements about the shoulder and hip compared with sedentary male subjects. It is unclear if these differences in ROM are related to strength, training type, and years of training experience or if individuals with less ROM have a better propensity to gain strength. The purpose of this study was to compare strength and ROM in male powerlifters and recreationally strength-trained male subjects and to determine if ROM would be an effective predictor of strength in these groups. Twelve powerlifters and 12 recreationally strength-trained control subjects completed 1 repetition maximum (1RM) squat and bench press testing. In a subsequent session, active ROM was measured, and velocity data were collected during submaximal squat repetitions. There was no significant difference (p > 0.05) between the groups for age, height, body mass, training experience, and training frequency. Powerlifters had significantly greater (p ≤ 0.05) training duration and absolute squat and bench press 1RM. Powerlifters had significantly less shoulder extension and horizontal abduction, and hip flexion, extension, and adduction than recreationally strength-trained men. Significant negative relationships were found between 2-lift Wilks score (body mass relative strength) and shoulder extension and horizontal abduction, as well as hip flexion and extension. In powerlifters, significant negative relationships were found between competition Wilks score, shoulder extension, and hip flexion. Because these relationships correspond to the bottom position of the squat and bench press, it may be best to ensure that shoulder extension and hip flexion remain sufficient to achieve competition depth.

Kinetics and Kinematics of the Free-Weight Back Squat and Loaded Jump Squat.

Thompson, SW, Lake, JP, Rogerson, D, Ruddock, A, and Barnes, A. Kinetics and kinematics of the free-weight back squat and loaded jump squat. J Strength Cond Res 37(1): 1-8, 2023-The aim of this study was to compare kinetics and kinematics of 2 lower-body free-weight exercises, calculated from concentric and propulsion subphases, across multiple loads. Sixteen strength-trained men performed back squat 1 repetition maximum (1RM) tests (visit 1), followed by 2 incremental back squat and jump squat protocols (visit 2) (loads = 0% and 30-60%, back squat 1RM). Concentric phase and propulsion phase force-time-displacement characteristics were derived from force plate data and compared using analysis of variance and Hedges' g effect sizes. Intrasession reliability was calculated using intraclass correlation coefficient (ICC) and coefficient of variation (CV). All dependent variables met acceptable reliability (ICC >0.7; CV < 10%). Statistically significant 3-way interactions (load × phase × exercise) and 2-way main effects (phase × exercise) were observed for mean force, velocity (30-60% 1RM), power, work, displacement, and duration (0%, 30-50% 1RM) ( p < 0.05). A significant 2-way interaction (load × exercise) was observed for impulse ( p < 0.001). Jump squat velocity ( g = 0.94-3.80), impulse ( g = 1.98-3.21), power ( g = 0.84-2.93), and work ( g = 1.09-3.56) were significantly larger across concentric and propulsion phases, as well as mean propulsion force ( g = 0.30-1.06) performed over all loads ( p < 0.001). No statistically significant differences were observed for mean concentric force. Statistically longer durations ( g = 0.38-1.54) and larger displacements ( g = 2.03-4.40) were evident for all loads and both subphases ( p < 0.05). Ballistic, lower-body exercise produces greater kinetic and kinematic outputs than nonballistic equivalents, irrespective of phase determination. Practitioners should therefore use ballistic methods when prescribing or testing lower-body exercises to maximize athlete's force-time-displacement characteristics.