Leg Press Exercise Research Articles

The Effect of Orally Dosed Levagen+™ (palmitoylethanolamide) on Exercise Recovery in Healthy Males-A Double-Blind, Randomized, Placebo-Controlled Study.

The aim of this study was to evaluate the effect of palmitoylethanolamide (PEA), a cannabimimetic compound and lipid messenger, on recovery from muscle damaging exercise. Twenty-eight healthy young male participants attended the laboratory four times on subsequent days. In the first visit, baseline characteristics were recorded before participants were randomized to consume either liquid PEA (167.5 mg Levagen+ with 832.5 mg maltodextrin) or a matched placebo (1 g maltodextrin) drink. Leg press exercise consisted of four sets at 80% of one repetition maximum followed by a performance set. Muscle soreness, thigh circumference, blood lactate concentration, biomarkers of muscle damage and inflammation, and transcription factor pathways were measured pre- and immediately post-exercise and again at 1, 2, 3, 24, 48, and 72 h post-exercise. The leg press exercise increased (p < 0.05) blood lactate concentration and induced muscle damage as evidenced by increased muscle soreness, thigh circumference, biomarkers of muscle damage, and concentrations of tumor necrosis factor-α. PEA reduced (p < 0.05) myoglobin and blood lactate concentrations and increased protein kinase B phosphorylation following exercise. Taken together, these results indicate PEA supplementation may aid in muscle recovery from repeat bouts of exercise performed within a short duration by reducing myoglobin and lactate concentration.

Acute responses of comprehensive gonadosteroids and corticosteroids to resistance exercise before and after 10weeks of supervised strength training.

What is the central question of this study? Although acute responses of the principal gonadosteroid and corticosteroid hormones to resistance exercise are well documented, there is no information regarding how the key lower-concentration intermediary hormones respond and potentially influence these hormonal pathways. What is the main finding and its importance? This study provides evidence for cascading conversions of some gonadosteroids, and the data suggest that the testosterone concentration increases independently of these hormones. These findings challenge future studies to determine the exact physiological roles of the lower-concentration gonadosteroids and corticosteroids during and immediately after resistance exercise. Resistance training is a potent stimulus for muscle growth, and steroid hormones are known to play a role in this adaptation. However, very little is known about the acute exercise-induced gonadosteroid and corticosteroid hormone responses, including those of key lower-concentration intermediate hormones. The present study determined the acute responses of these steroid hormone families using quantitative ultra-high performance liquid chromatography tandem mass spectrometry after resistance exercise in strength-trained men. Venous and fingertip blood samples were obtained pre-, mid-, 5min post- and 15min post-resistance exercise, both before and after 10weeks of supervised resistance training. The experimental resistance exercise sessions consisted of three sets of 10 repetitions of bilateral leg-press exercise and three sets of 10 repetitions of unilateral knee-extension exercise, with 2 and 1min recovery between sets, respectively. Statistically significant (P<0.05) increases in the concentration of hormones in the gonadosteroid [including dehydroepiandrosterone (DHEA), androstenedione, testosterone and estrone] and the corticosteroid (including cortisol, corticosterone and cortisone) families were demonstrated after both experimental resistance exercise sessions, irrespective of training status. Correlation analyses revealed relationships between the following hormones: (i) DHEA and androstenedione; (ii) DHEA and cortisol; (iii) androstenedione and estrone; and (iv) 11-deoxycortisol and cortisol. Testosterone appears to increase acutely and independently of other intermediary hormones after resistance exercise. In conclusion, lower-concentration intermediary gonadosteroids (e.g. estrone) and corticosteroids (e.g. corticosterone) respond robustly to resistance exercise in strength-trained men, although it seems that testosterone concentrations are regulated by factors other than the availability of precursor hormones and changes in plasma volume.

The Effect of ProHydrolase® on the Amino Acid and Intramuscular Anabolic Signaling Response to Resistance Exercise in Trained Males

This double-blind study examined effects of a protease enzyme blend (Prohydrolase®) added to whey protein on post-resistance exercise aminoacidemia and intramuscular anabolic signaling were investigated in ten resistance-trained males. Participants completed 4 sets of 8–10 repetitions in the leg press and leg extension exercises at 75% of 1-repetition maximum. Participants then consumed either 250 mg of Prohydrolase® + 26 g of whey protein (PW), 26 g whey alone (W), or non-nutritive control (CON) in counterbalanced order. Blood samples were obtained prior to exercise (baseline) and then immediately-post (IP), 30-, 60-, 90-, 120-, and 180-min post-exercise. Muscle biopsies were taken at baseline, 1-h (1H), and 3-h (3H) post-exercise. Phosphorylation of AKTSer437 was decreased (3H only: p < 0.001), mTORSer2448 was increased (1H: p = 0.025; 3H: p = 0.009), and p70S6KThr412 remained unchanged similarly for each condition. Plasma leucine, branch-chained amino acids, and essential amino acid concentrations for PW were significantly higher than CON (p < 0.05) at 30 min and similar to W. Compared to IP, PW was the only treatment with elevated plasma leucine levels at 30 min (p = 0.007; ∆ = 57.8 mmol/L, 95% Confidence Interval (CI): 20.0, 95.6) and EAA levels at 180 min (p = 0.003; ∆ = 179.1 mmol/L, 95% CI: 77.5, 280.7). Area under the curve amino acid analysis revealed no differences between PW and W. While no different than W, these data indicate that PW was the only group to produce elevated amino acid concentrations 30-min and 180-min post-ingestion.

Muscular adaptations to periodized resistance-training in older adults

Summary Objectives Due to skeletal muscle wasting (sarcopenia) older adults rely on a larger proportion of their remaining skeletal muscle to generate force and power for everyday activities. As a consequence, premature fatigue and a cycle of further inactivity and disability ensue. Thus, different fitness components, such as muscular strength and endurance may need to be targeted to counteract functional decline. Although, resistance training periodization has been shown to result in superior muscle strength adaptations in younger populations, the effects are less clear in older adults. Equipment and methods We recruited previously trained, older male and female subjects (n = 15, > 60 years of age) for a ten-week pre- post-test design, two days/week periodized resistance training program. The program consisted of one day high-intensity/low volume [∼85% of the estimated 1 repetition maximum (RM) with 6 repetitions] and one day low-moderate intensity/high volume (∼67% of the estimated 1RM with 12 repetitions) training. Results 1RM increased significantly (P = 0.000) for both the leg press and chest press exercises after resistance training by 17.9 and 17.3%, respectively. Moreover, the subjects completed more repetitions with the higher load (60% of post-training 1RM) after training, thus volume load (VL) (number of repetitions × 60% of 1RM load) increased significantly (P = 0.000) in both the leg press (43.3%) and the chest press (21.6%) exercises. Chest press strength and endurance improvements showed a significant (P = 0.017) moderate correlation (r = 0.59). On the other hand, no changes were detected in body composition and lean mass as a result of the program. Resistance training periodization is a feasible strategy in older populations to improve muscular strength and muscular endurance simultaneously. The results indicate that exercise professionals can utilize even low frequency periodization training to improve muscle strength and endurance in active older adults in a time-efficient manner.

Effects of daily 24-gram doses of rice or whey protein on resistance training adaptations in trained males

BackgroundLarge (48-g), isonitrogenous doses of rice and whey protein have previously been shown to stimulate similar adaptations to resistance training, but the impact of consuming smaller doses has yet to be compared. We evaluated the ability of 24-g doses of rice or whey protein concentrate to augment adaptations following 8 weeks of resistance training.MethodsHealthy resistance-trained males (n = 24, 32.8 ± 6.7 years, 179.3 ± 8.5 cm, 87.4 ± 8.5 kg, 27.2 ± 1.9 kg/m2, 27.8 ± 6.0% fat) were randomly assigned and matched according to fat-free mass to consume 24-g doses of rice (n = 12, Growing Naturals, LLC) or whey (n = 12, NutraBio Labs, Inc.) protein concentrate for 8 weeks while completing a standardized resistance training program. Body composition (DXA), muscular strength (one-repetition maximum [1RM]) and endurance (repetitions to fatigue [RTF] at 80% 1RM) using bench press (BP) and leg press (LP) exercises along with anaerobic capacity (Wingate) were assessed before and after the intervention. Subjects were asked to maintain regular dietary habits and record dietary intake every 2 weeks. Outcomes were assessed using 2 × 2 mixed (group x time) factorial ANOVA with repeated measures on time and independent samples t-tests using the change scores from baseline. A p-value of 0.05 and 95% confidence intervals on the changes between groups were used to determine outcomes.ResultsNo baseline differences (p > 0.05) were found for key body composition and performance outcomes. No changes (p > 0.05) in dietary status occurred within or between groups (34 ± 4 kcal/kg/day, 3.7 ± 0.77 g/kg/day, 1.31 ± 0.28 g/kg/day, 1.87 ± 0.23 g/kg/day) throughout the study for daily relative energy (34 ± 4 kcals/kg/day), carbohydrate (3.7 ± 0.77 g/kg/day), fat (1.31 ± 0.28 g/kg/day), and protein (1.87 ± 0.23 g/kg/day) intake. Significant main effects for time were revealed for body mass (p = 0.02), total body water (p = 0.01), lean mass (p = 0.008), fat-free mass (p = 0.007), BP 1RM (p = 0.02), BP volume (p = 0.04), and LP 1RM (p = 0.01). Changes between groups were similar for body mass (− 0.88, 2.03 kg, p = 0.42), fat-free mass (− 0.68, 1.99 kg, p = 0.32), lean mass (− 0.73, 1.91 kg, p = 0.37), fat mass (− 0.48, 1.02 kg, p = 0.46), and % fat (− 0.63, 0.71%, p = 0.90). No significant between group differences were seen for BP 1RM (− 13.8, 7.1 kg, p = 0.51), LP 1RM (− 38.8, 49.6 kg, p = 0.80), BP RTF (− 2.02, 0.35 reps, p = 0.16), LP RTF (− 1.7, 3.3 reps, p = 0.50), and Wingate peak power (− 72.5, 53.4 watts, p = 0.76) following the eight-week supplementation period.ConclusionsEight weeks of daily isonitrogenous 24-g doses of rice or whey protein in combination with an eight-week resistance training program led to similar changes in body composition and performance outcomes. Retroactively registered on as NCT04411173.

Comparison of methods to determine the lactate threshold during leg press exercise in long-distance runners

Abstract Aims: To determine lactate threshold (LT) by three different methods (visual inspection, algorithmic adjustment, and Dmax) during an incremental protocol performed in the leg press 45° and to evaluate correlation and agreement among these different methods. Methods: Twenty male long-distance runners participated in this study. Firstly, participants performed the dynamic force tests in one-repetition maximum (1RM). In the next session, completed an incremental protocol consisted of progressive stages of 1 min or 20 repetitions with increments of 10, 20, 25, 30, 35, and 40% 1RM. From 40% 1RM, increments corresponding to 10% 1RM were performed until a load in which the participants could not complete the 20 repetitions. A rest interval of 2 min was observed between each stage for blood collection and adjustment of the workloads for the next stage. Results: Our results showed no significant difference in relative load (% 1RM), good correlations, and high intraclass correlation coefficients (ICC) between algorithmic adjustment and Dmax (p = 0.680, r = 0.92; ICC = 0.959), algorithmic adjustment and visual inspection (p = 0.266, r = 0.91; ICC = 0.948), and Dmax and visual inspection (p = 1.000, r = 0.88; ICC = 0.940). In addition, the Bland-Altman plot and linear regression showed agreement between algorithmic adjustment and Dmax (r2 = 0.855), algorithmic adjustment and visual inspection (r2 = 0.834), and Dmax and visual inspection (r2 = 0.781). Conclusion: The good correlation and high agreement among three methods suggest their applicability to determine LT during an incremental protocol performed in the leg press 45°. However, the best agreement found between mathematical methods suggests better accuracy.

Effects of Eccentric-Focused Versus Conventional Training on Lower Limb Muscular Strength in Older People: A Systematic Review With Meta-Analysis.

Eccentric-focused training promotes greater gains in muscle strength compared to other types of training in adults. However, for older people, these findings are still not well understood. A systematic review and meta-analysis were performed using manuscripts that performed eccentric-focused (ET) and conventional resistance training (CT) at least four weeks and evaluated maximum muscle strength through tests of maximum repetitions in weight machine exercises (knee extension and leg press exercises). Five studies were included (n=138). Increases in muscle strength were found in both resistance training groups, without difference between them through meta-analysis. However, a large effect size has been observed only in ET. The findings suggest that resistance training protocols are similar to improve maximal strength in older people, despite larger effect sizes for eccentric-focused training.

Effects of Pre-exhaustion Versus Traditional Resistance Training on Training Volume, Maximal Strength, and Quadriceps Hypertrophy.

BackgroundThe pre-exhaustion (PreEx) method is used as a resistance training (RT) method to increase muscle mass, yet the chronic effects of this method are poorly understood.ObjectiveAlthough readily prescribed as a RT method for promotion of muscle hypertrophy, few researches give light to gains made after chronic PreEx RT. Therefore, we compared the effects of traditional versus PreEx RT programs on muscle strength, body composition, and muscular hypertrophy in adult males.MethodsUntrained subjects (age: 31.37 ± 6.83 years; height: 175.29 ± 5.52 cm; body mass: 82.04 ± 13.61 kg; 1RM leg press: 339.86 ± 61.17 kg; 1RM leg extension: 121.71 ± 11.93 kg) were submitted to 9 weeks of RT with weekly sessions. Traditional (TRT) group (n = 12) performed three sets at 45° of leg press exercise at 75% of 1RM, PreEx group (n = 12) completed a set to failure on a leg extension machine prior to the leg press, and the control (CON) group (n = 7) did not train. Maximum strength, muscle thickness, and body composition were analyzed.ResultsPreEx group increased in maximal strength on leg press (16 ± 8%) and leg extension (17 ± 11%), while the TRT group improved by 15 ± 9 and 11 ± 4%, respectively. The thickness of the quadriceps muscles increased for both intervention groups. Specifically, the post-training thickness of the vastus lateralis was significantly higher for PreEx (55%) compared to the CON group. The TRT group presented a greater loss of total and thigh fat mass when compared with the PreEx method. These results were found in the presence of a lower training load for the PreEx group.ConclusionThe PreEx training can decrease the total training volume while maintaining results in strength and hypertrophy when comparing to TRT. However, TRT may be optimal if the goal is to decrease fat mass.

PENGARUH LATIHAN HURDLE JUMP DAN LATIHAN LEG PRESS TERHADAP KEMAMPUAN DAYA LEDAK OTOT TUNGKAI PADA MAHASISWA UKM BOLA VOLI IKIP MATARAM TAHU 2019

The problem in this research is stated as; Is there any effect of Hurdle Jump Exercise and Leg Press Exercise toward the Limb Muscle Explosive Power ability on the students of UKM volleyball IKIP Mataram in 2019. The sampling method uses the population study and the total sampling was 12 students of UKM volleyball IKIP Mataram in 2017/2018. The data collection uses documentation, performance test, and vertical jump test. The data analysis technique uses the t-test at 5% significant level. The result showed that the effect of hurdle jump exercise toward ability of limb muscle explosive power is higher than the t-table (5.081 &gt; 2.571). While the limb press exercises on the ability of limb muscle explosive power showed that t-score is higher than t-table (4.164 &gt; 2.571). As a conclusion, there is effect of Hurdle Jump Exercise and Leg Press Exercises toward Limb Muscle Explosive Power Ability on the students of UKM volleyball IKIP Mataram in 2019.

Perceptual responses to continuous versus intermittent blood flow restriction exercise: A randomized controlled trial

We investigated the perceptual responses to resistance exercise (RE) with continuous and intermittent blood flow restriction (BFR). Fourteen males randomly completed the following exercise conditions: low-load RE with continuous BFR (cBFR), low-load RE with intermittent BFR (iBFR), low-load RE without BFR (LI), and traditional high-load RE (HI). Participants completed 4 sets of 30-15-15-15 repetitions of bilateral leg press and knee extension exercises during the low-load conditions, at 20% of one-repetition maximum (1-RM), a 1.5‑sec metronome-controlled pace, with a 1-min rest interval between sets; HI consisted of 4 sets of 10 repetitions of the same exercises, at 70% 1-RM, with the same pace and rest interval. Ratings of perceived exertion (RPE) and discomfort were assessed using psychometric scales before exercise and after each set. RPE displayed no significant differences (p > 0.05) between the BFR conditions for either exercise. Additionally, both BFR conditions elicited significantly (p < 0.05) greater RPE than LI and significantly (p <0.05) lower RPE than HI during both exercises. Rating of discomfort displayed no significant differences between BFR conditions during the first two sets of leg press; however, cBFR evoked greater discomfort compared to iBFR during the last two sets. There were no significant (p > 0.05) differences observed between conditions during the knee extension exercise. Rating of discomfort was similar between the BFR and HI conditions and each were significantly greater than LI during both exercises. Therefore, cBFR and iBFR seem to produce similar perceptual responses, which are greater than LI and lower than HI, but similar in regards to discomfort.

Acute Hemodynamic Responses to Repetitions to Failure Using Different Resistance Exercises and Protocols in Normotensive Men: A crossover study

ABSTRACTThe present crossover design study investigated acute hemodynamic responses to two sets of leg press (LP) and bench press (BeP) at 10 and 20 repetition maximum (RM) in ten normotensive young men. At the end of each set, an increase in systolic blood pressure (SBP), heart rate (HR), and rate pressure product (RPP) was observed (p < .01), with no differences between intensities, but SBP was greater during the LP exercise (p < .01). Lower resting values of diastolic blood pressure (DBP) were observed in the post-BeP exercise period (p < .05), suggesting that DBP post-exercise hypotension may be more evident after upper-limb exercise.

Hunger is suppressed after resistance exercise with moderate-load compared to high-load resistance exercise: the potential influence of metabolic and autonomic parameters

The purpose of present study was to compare the effects of moderate-load versus high-load resistance exercise (RE) on hunger response, blood lactate, glucose, and autonomic modulation in trained men, and to examine the correlations between these parameters. For this, 11 recreationally resistance-trained males performed 2 randomized trials: moderate-load (6 sets at 70% 1-repetition maximum (1RM) and a 90-s rest interval between sets) and high-load (6 sets at 90% 1RM and a 180-s rest interval between sets) leg-press exercise until movement failure. The subjective rating of hunger was obtained through a visual analog scale. Glucose and lactate concentration were evaluated at rest, immediately after exercise, and 30 min after exercise. Heart rate variability was recorded at baseline and during recovery (until 30 min after exercise) to assess autonomic modulation. The moderate-load condition induced lower subjective hunger ratings than the strength condition immediately after exercise (19.7 ± 16.6 vs 47.3 ± 27.7 mm), 30 min after exercise (33.6 ± 22.9 vs 58.5 ± 29.9 mm), and 60 min after exercise (43.8 ± 26.6 vs 67.8 ± 27.9 mm) (p < 0.05) and lower area under the curve hunger in relation to the high-load condition (p < 0.006). Moderate-load RE presented greater lactate concentration and induced slower heart rate variability recovery in relation to high-load RE (p < 0.05), but no difference was found in glucose, as well as no correlations between any of the variables investigated. In conclusion, moderate-load RE induced lower subjective hunger ratings, slower recovery of the parasympathetic nervous system, and higher lactate concentration in relation to high-load RE, but the metabolic variables were not correlated with hunger suppression.

Characteristics of load and EMG during different knee angled bilateral and unilateral leg press exercises in jumpers

Characteristics of load and EMG during different knee angled bilateral and unilateral leg press exercises in jumpers

Blood-Flow Restriction Resistance Exercise Promotes Lower Pain and Ratings of Perceived Exertion Compared With Either High- or Low-Intensity Resistance Exercise Performed to Muscular Failure.

Given the comparable muscle hypertrophy constantly observed between blood-flow restriction exercise (BFR-RE) and conventional resistance exercise, understanding their particular rating of perceived exertion (RPE) and pain may help to better prescribe exercise at a low-discomfort level, thus increasing its feasibility. Randomized crossover study. To compare the RPE and pain response between conventional high- (HI-RE) and low-intensity resistance exercise (LI-RE) protocols to failure with a nonmuscular failure LI-RE associated with BFR-RE. A total of 12 men (age: 20 [3]y; body mass: 73.5 [9]kg; height: 174 [6]cm). Four sets of 45° leg-press exercises in 3 different conditions: (1)BFR-RE (15 repetitions; 30% 1-repetition maximum), (2)HI-RE (80% 1-repetition maximum to muscular failure), and (3)LI-RE (30% 1-repetition maximum to muscular failure). RPE and pain were assessed immediately before exercise session and after the end of each of the 4 sets. RPE and pain levels increased throughout the exercise sets for all RE protocols (all, Ps < .05). HI-RE and LI-RE protocols showed similar increase in RPE and pain levels during all exercise sets (P < .05); however, both protocols demonstrated higher RPE and pain response compared with BFR-RE after each of the 4 sets (all Ps < .05 between-group comparisons). Our results demonstrated that both HI-RE and LI-RE to muscular failure resulted in similar and significant increases in RPE and pain levels, regardless of exercise intensity. In addition, nonmuscular failure BFR-RE also increased RPE and pain response, however, to a lower extent compared with either HI-RE or LI-RE.

Movement velocity can be used to estimate the relative load during the bench press and leg press exercises in older women.

BackgroundMovement velocity has been proposed as an effective tool to prescribe the load during resistance training in young healthy adults. This study aimed to elucidate whether movement velocity could also be used to estimate the relative load (i.e., % of the one-repetition maximum (1RM)) in older women.MethodsA total of 22 older women (age = 68.2 ± 3.6 years, bench press 1RM = 22.3 ± 4.7 kg, leg press 1RM = 114.6 ± 15.9 kg) performed an incremental loading test during the free-weight bench press and the leg press exercises on two separate sessions. The mean velocity (MV) was collected with a linear position transducer.ResultsA strong linear relationship between MV and the relative load was observed for the bench press (%1RM = −130.4 MV + 119.3; r2 = 0.827, standard error of the estimate (SEE) = 6.10%1RM, p < 0.001) and leg press exercises (%1RM = −158.3 MV + 131.4; r2 = 0.913, SEE = 5.63%1RM, p < 0.001). No significant differences were observed between the bench press and leg press exercises for the MV attained against light-medium relative loads (≤70%1RM), while the MV associated with heavy loads (≥80%1RM) was significantly higher for the leg press.ConclusionsThese results suggest that the monitoring of MV could be useful to prescribe the loads during resistance training in older women. However, it should be noted that the MV associated with a given %1RM is significantly lower in older women compared to young healthy individuals.

Motor unit discharge rate and the estimated synaptic input to the vasti muscles is higher in open compared with closed kinetic chain exercise.

Conflicting results have been reported on whether closed kinetic chain exercises (such as a leg press) may induce more balanced activation of vastus medialis (VM) and lateralis (VL) muscles compared with open kinetic chain exercise (such as pure knee extension). This study aimed to 1) compare between-vasti motor unit activity and 2) analyze the combined motor unit behavior from both muscles between open and closed kinetic chain exercises. Thirteen participants (four women, mean ± SD age: 27 ± 5 yr) performed isometric knee extension and leg press at 10, 30, 50, 70% of the maximum voluntary torque. High density surface EMG signals were recorded from the VM and VL and motor unit firings were automatically identified by convolutive blind source separation. We estimated the total synaptic input received by the two muscles by analyzing the difference in discharge rate from recruitment to target torque for motor units matched by recruitment threshold. When controlling for recruitment threshold and discharge rate at recruitment, the motor unit discharge rates were higher for knee extension compared with the leg press exercise at 50% [estimate = 1.2 pulses per second (pps), standard error (SE) = 0.3 pps, P = 0.0138] and 70% (estimate = 2.0 pps, SE = 0.3 pps, P = 0.0001) of maximal torque. However, no difference between the vasti muscles were detected in both exercises. The estimates of synaptic input to the muscles confirmed these results. In conclusion, the estimated synaptic input received by VM and VL was similar within and across exercises. However, both muscles had higher firing rates and estimated synaptic input at the highest torque levels during knee extension. Taken together, the results show that knee-extension is more suitable than leg-press exercise at increasing the concurrent activation of the vasti muscles.NEW & NOTEWORTHY There is a significant debate on whether open kinetic chain, single-joint knee extension exercise can influence the individual and combined activity of the vasti muscles compared with closed kinetic chain, multijoint leg press exercise. Here we show that attempting to change the contribution of either the vastus medialis or vastus lateralis via different forms of exercise does not seem to be a viable strategy. However, the adoption of open kinetic chain knee extension induces greater discharge rate and estimated synaptic input to both vasti muscles compared with the leg press.

Examination of the comfort and pain experienced with blood flow restriction training during post-surgery rehabilitation of anterior cruciate ligament reconstruction patients: A UK National Health Service trial

ObjectiveExamine the comfort and pain experienced with blow flow restriction resistance training (BFR-RT) compared to standard care heavy load resistance training (HL-RT) during anterior cruciate ligament reconstruction (ACLR) patient rehabilitation. DesignRandomised controlled trial. SettingUnited Kingdom National Health Service. ParticipantsTwenty eight patients undergoing unilateral ACLR surgery with hamstring autograft were recruited. Following surgery participants were block randomised to either HL-RT at 70% repetition maximum (1RM) (n = 14) or BFR-RT (n = 14) at 30% 1RM and completed 8 weeks of twice weekly unilateral leg press training on both limbs. Main outcome measuresPerceived knee pain, muscle pain and rating of perceived exertion (RPE) were assessed using Borg’s (1998) RPE and pain scales during training. Knee pain was also assessed 24 h post-training. ResultsThere were no adverse events. Knee pain was lower with BFR-RT during (p < 0.05) and at 24 h post-training (p < 0.05) with BFR-RT for all sessions. Muscle pain was higher (p < 0.05) with BFR-RT compared to HL-RT during all sessions. RPE remained unchanged (p > 0.05) for both BFR-RT and HL-RT. ConclusionACLR patients experienced less knee joint pain and reported similar ratings of perceived exertion during and following leg press exercise with BFR-RT compared to traditional HL-RT. BFR-RT may be more advantageous during the early phases of post-surgery ACLR rehabilitation.

Familiarization With Airflow-Restriction Mask During Resistance Exercise: Effect on Tolerance and Total Volume.

Teodoro, CL, Gáspari, AF, Berton, R, Barbieri, JF, Silva, M, Castaño, LAA, Guimarães, P, and Moraes, AC. Familiarization with airflow-restriction mask during resistance exercise: Effect on tolerance and total volume. J Strength Cond Res 33(7): 1762-1765, 2019-This study investigated whether familiarization with the airflow-restriction mask (AIRfr) increases tolerance and avoids negative effects on performance of resistance exercise (RE). Ten resistance-trained male subjects performed a familiarization session (FAM), followed by 2 testing sessions, with the AIRfr and without airflow restriction (SHAM) in a counterbalanced and randomized cross-over design. The FAM was performed with the same number of sets, load, and level of airflow-restriction as the AIRfr experimental session. Each session consisted of 4 sets of the leg press exercise with 70% 1 repetition maximum until voluntary failure and a 90-second rest interval between sets. During the FAM, 4 of the 10 subjects expressed some intolerance to the use of airflow restriction. Total volume was lower in the FAM than in the AIRfr (p = 0.01) and the SHAM (p = 0.02), whereas no differences were observed between the AIRfr and the SHAM (p = 0.90). The first use of the AIRfr may not be well tolerated by all subjects. However, a familiarization session with the AIRfr avoids negative interferences in the total volume during RE.

Blood Flow Restriction Training Does Not Improve Quadriceps Strength After Anterior Cruciate Ligament Reconstruction

Objectives: Blood flow restriction training (BFRT) involves obstruction of venous outflow of working muscles during exercise and may lead to more substantial recovery of quadriceps strength after anterior cruciate ligament (ACL) reconstruction. The purpose of this study is to examine the effects of BFRT in ACL reconstruction patients before and after exposure to BFRT. Methods: This study was a randomized controlled trial in which 36 patients who had torn their ACL and were scheduled to undergo ACL reconstructive surgery (ACLR) with an autograft were randomized to receive exercise with BFRT (N=18) or exercise without BFRT (N=18). Participants in both groups performed the same exercise, but either did or did not have blood flow restricted. The exercise component of the intervention consisted of all subjects performing a single-leg isokinetic leg press, at an intensity of 70% of the subjects’ one-repetition maximum, for four sets of ten repetitions two times per week for 8 weeks beginning at 8 weeks post-operatively. Patients randomized to the BFRT group performed the leg-press exercise with a blood flow restriction cuff applied to the thigh and set to a limb occlusion pressure of 80 percent. All participants were concurrently undergoing standard ACL rehabilitation at the same physical therapy clinic. Bilateral isometric (recorded at a knee angle of 90°) and isokinetic (60°/second) quadriceps strength were recorded using a Biodex dynamometer (System 4, Shirley, NY) prior to ACLR and after the conclusion of the 8-week intervention. Peak isometric and isokinetic quadriceps strength were utilized to generate isometric and isokinetic quadriceps symmetry indices ((ACLR limb strength/Healthy limb strength) x100). Change from baseline symmetry scores were then generated using the following equation: (post-intervention symmetry - pre-intervention symmetry)/pre-intervention symmetry in order to account for possible differences in strength between groups prior to intervention delivery. Change from baseline isometric and isokinetic quadriceps symmetry scores were then compared between groups (exercise with BFRT, exercise without BFRT) using one-way analysis of variance tests with an a priori α set to P≤ 0.05. Effect sizes (Cohen’s d) and 95% confidence intervals were also computed. Results: No significant differences were found for change from baseline isokinetic quadriceps symmetry index (P=0.39, BFRT mean=-0.05, Control mean=-0.19) or change from baseline isometric quadriceps symmetry index (P=0.62, BFRT mean=-0.04, control mean=-0.10). The effect sizes for isokinetic quadriceps symmetry index (d=0.28, 95% CI= -0.37, 0.93) and isometric quadriceps symmetry (d=0.16, 95% CI= -0.49, 0.80) were small with confidence intervals that crossed zero. Conclusion: An 8-week blood flow resistance training + exercise intervention did not increase quadriceps muscle strength in patients who had undergone ACL reconstruction. Based on our findings, application of blood flow restriction training in ACL reconstruction patients to improve quadriceps strength may not be warranted. Future studies may benefit from a longer follow-up and larger sample size.

MTORC1 Signaling in Individual Human Muscle Fibers Following Resistance Exercise in Combination With Intake of Essential Amino Acids

Human muscles contain a mixture of type I and type II fibers with different contractile and metabolic properties. Little is presently known about the effect of anabolic stimuli, in particular nutrition, on the molecular responses of these different fiber types. Here, we examine the effect of resistance exercise in combination with intake of essential amino acids (EAA) on mTORC1 signaling in individual type I and type II human muscle fibers. Five strength-trained men performed two sessions of heavy leg press exercise. During exercise and recovery, the subjects ingested an aqueous solution of EAA (290 mg/kg) or flavored water (placebo). Muscle biopsies were taken from the vastus lateralis before and 90 min after exercise. The biopsies were freeze-dried and single fibers dissected out and weighed (range 0.95–8.1 μg). The fibers were homogenized individually and identified as type I or II by incubation with antibodies against the different isoforms of myosin. They were also analyzed for both the levels of protein as well as phosphorylation of proteins in the mTORC1 pathway using Western blotting. The levels of the S6K1 and eEF2 proteins were ~50% higher in type II than in type I fibers (P < 0.05), but no difference was found between fiber types with respect to the level of mTOR protein. Resistance exercise led to non-significant increases (2–3-fold) in mTOR and S6K1 phosphorylation as well as a 50% decrease (P < 0.05) in eEF2 phosphorylation in both fiber types. Intake of EAA caused a 2 and 6-fold higher (P < 0.05) elevation of mTOR and S6K1 phosphorylation, respectively, in both type I and type II fibers compared to placebo, with no effect on phosphorylation of eEF2. In conclusion, protein levels of S6K1 and eEF2 were significantly higher in type II than type I fibers suggesting higher capacity of the mTOR pathway in type II fibers. Ingestion of EAA enhanced the effect of resistance exercise on phosphorylation of mTOR and S6K1 in both fiber types, but with considerable variation between single fibers of both types.