Resistance Training Experience Research Articles

No sex differences in time-to-task failure and neuromuscular patterns of response during submaximal, bilateral, isometric leg extensions.

In general, it has been suggested that females are more fatigue-resistant than males, with the magnitude of difference being most pronounced during low-intensity sustained contractions. However, the mechanisms for the apparent sex difference have not yet been fully elucidated in the literature. This study aimed to examine sex-related differences in fatigability and patterns of neuromuscular responses for surface electromyographic (sEMG) and mechanomyographic (sMMG) amplitude and frequency (MPF) characteristics during a sustained submaximal bilateral, isometric leg extension muscle action. A sample of 20 young recreationally active males and females with previous resistance training experience performed a sustained, submaximal, bilateral isometric leg extension until task failure. Time-to-task failure was compared using a nonparametric bootstrap of the 95% confidence interval for the mean difference between males and females. Additionally, patterns of response for sEMG and sMMG amplitude and MPF of the dominant limb were examined using linear mixed effect models. There were no differences in time-to-task failure between males and females. Additionally, neuromuscular responses revealed similar patterns of responses between males and females. Interestingly, sEMG amplitude and sMMG amplitude and MPF all revealed non-linear responses, while sEMG MPF demonstrated linear responses. These data revealed that time-to-task failure was not different between males and females during sustained submaximal bilateral, isometric leg extension. Interestingly, the parallel, non-linear, increases in sEMG and sMMG amplitude may indicate fatigue induced increases in motor unit recruitment, while the parallel decreases in sMMG MPF may be explained by the intrinsic properties of later recruited motor units, which may have inherently lower firing rates than those recruited earlier.

Exploring Temporal and Intensity Effects of Resistance Exercise on Inhibition: A Four-Arm Crossover Randomized Controlled Trial.

Given the recognized benefits of resistance exercise on both physical and cognitive domains, elucidating how to maximize its benefit is pivotal. This study aims to evaluate these effects in terms of their timing and intensity on cognitive performance. This was a four-arm, crossover randomized controlled trial. Healthy college-aged male adults with recreational resistance training experience participated in this study. Participants completed three separate sessions of circuit barbell resistance exercises, including back squat, press, and deadlift. Each session corresponded to a different intensity level: 65% 1RM, 72% 1RM, and 78% 1RM. Each session consisted of 5 repetitions across 3 sets, with a 3-minute rest between exercises and sets. For the control condition, participants engaged in a reading activity for the same duration. The subjective exercise intensity was measured using the rating of perceived exertion and repetitions in reserve immediately after each set. The primary outcome was the temporal effect of acute resistance exercise on inhibition, measured by the Stroop color-word task. The secondary outcome was the effect of different intensities. 30 out of 31 recruited participants were randomized, with 28 completing all experiment sessions. Using repeated measures correlation (rrm), a linear temporal effect was observed on accuracy-adjusted congruent reaction time: rrm = 0.114, p = 0.045, 95% CI [0.002, 0.223]. Participants responded 19.1 ms faster than the control condition approximately 10 minutes post-intervention. This advantage, however, gradually declined at a rate of 4.3 ms every 15 minutes between 10-55 minutes post-intervention. In contrast, no significant effects were detected for incongruent trials or the Stroop effect. When examining the linear relationship across exercise intensities, no significant correlations emerged for congruent trials. Resistance exercise demonstrates a temporal effect on cognitive performance, particularly in reaction speed for congruent trials, without significant changes in incongruent trials or the overall Stroop effect. The findings highlight the importance of timing in leveraging the cognitive benefits of acute resistance exercise, suggesting a window of enhanced cognitive performance following exercise. However, this study has a limitation regarding Type I error inflation, due to multiple measurements of cognitive performance being undertaken, suggesting caution in interpreting the observed temporal effects. Practically, scheduling crucial, cognitively demanding tasks within 10-60 minutes post-exercise may maximize benefits, as positive effects diminish after this period.

Association between Serum Biomarkers of Muscle Damage after Isokinetic Eccentric Exercise in Trained Males and Females

Eccentric exercise is well-known to induce muscle damage, and biomarkers may be related to the magnitude of impact on muscle force and muscle soreness after exercise. However, this phenomenon still needs to be investigated in more detail. The present study aimed to analyze if a correlation between muscle force, soreness, and biomarkers after eccentric exercise exists in healthy, trained 11 males and females. Eleven volunteers with previous resistance training experience performed 6 x 10 maximal isokinetic eccentric contractions of the elbow flexors in the muscle performance laboratory up to 72 hours after exercise. Peak torque was measured by maximal voluntary isometric contractions (MVIC) and muscle soreness by visual analogic scale (VAS) before, 24h, 48h, and 72h after the isokinetic eccentric exercise protocol. A fluorescence immunoassay analyzer determined Myoglobin and C-reactive protein levels. The MVIC significantly decreased while muscle soreness increased 24h, 48h, and 72h post eccentric exercise. Myoglobin significantly increased 48h and 72h after exercise. Muscle soreness was inversely correlated with MVIC 24h, 48h, and 72h and positively correlated with myoglobin 48h and 72h after eccentric exercise. The myoglobin was not correlated with muscle force. No significant correlation between C-reactive protein and muscle soreness and MVIC was found. In conclusion, our data suggest that myoglobin could be a valuable biomarker to be assessed alongside exercise-induced muscle soreness.

Feasibility and Usefulness of Repetitions-In-Reserve Scales for Selecting Exercise Intensity: A Scoping Review.

The intensity of resistance training (RT) exercise is an important consideration for determining relevant health and performance-related outcomes. Yet, current objective exercise intensity measures present concerns in terms of viability or cost. In response to these concerns, repetition-in-reserve (RIR) scales may represent an adequate method of measuring and regulating intensity. However, no recent review has focused on how RIR scales have been used for this purpose in prior research. We prepared the present scoping review to analyze the feasibility and usefulness of RIR scales in selecting RT intensity. We conducted a systematic search in PubMed, SPORTDiscus, PsycINFO, and ClinicalTrials.gov databases (last search date April 2023) for experimental and non-experimental studies that utilized an RIR scale to measure proximity to failure in RT activities with apparently healthy individuals of any age. We qualitatively analyzed 31 studies (N = 855 mostly male adult participants) published between 2012-2023. RIR scales appeared to be contextually feasible and useful in prescribing and adjusting RT intensity. The most common trend in this research was to prescribe a target RIR and adjust the exercise load for a desired proximity to muscle failure. Additionally, when measuring proximity to failure as an outcome of interest, the literature suggests that the RIR prediction should be made close to task failure to increase its accuracy. Future research should further explore the impact of sex, RT experience, exercise selection, and muscle conditioning on the overall RIR approach.

Field-based fitness measures improve via an immersive virtual reality exergaming platform: a randomized controlled trial

While there has been a recent onslaught of traditional lab-based fitness measures in immersive virtual reality (IVR) exergaming research, there remains a paucity in the field-based fitness domain, which refers to assessments made outside a formal laboratory setting which are easier, cheaper, and have more practical application. This study aimed to assess changes in field-based fitness tests including the 1-mile run, 20-m dash, multiple single-leg hop-stabilization test, Abalakov jump, and 5-10-5 Pro Agility test during a 1-month workout protocol and to compare differences between groups assigned to either an IVR machine-directed exergaming platform or a traditional, self-directed cable-resistance training control (SELF). Eighteen (7 females) college-aged participants with little resistance training experience were randomized to IVR or SELF and worked out thrice weekly for 4 weeks (12 sessions). Wilcoxon rank-sum tests were performed for continuous variables to assess significance. Compared to SELF, the IVR group had significantly better performance improvements in 20 m dash (−0.1s vs. 0.0s, p = 0.022), 5-10-5 Pro Agility Test (−0.1s vs. −0.0s, p = 0.003), Abalakov Jump (5.8 cm vs. 2.0 cm, p = 0.0013), 1-Mile Run (−11.0s vs. −2.0s, p = 0.008), and Multiple Single-Leg Hop-Stabilization Test with their dominant (−9.0s vs. 1.0s, p = 0.0015) and non-dominant (−8.0s vs. 1.0s, p = 0.003) legs. This training study demonstrates that IVR exergaming, more so than those that traditionally resistance train (SELF), can improve many field-based fitness components including agility, balance and stability, speed/acceleration, cardiovascular endurance, and lower-body power.

High‐frequency resistance training improves maximal lower‐limb strength more than low frequency

AbstractThis study compared the effects of a weekly lower body resistance‐training program divided into low frequency (LOW, one long session) versus high frequency (HIGH, four shorter sessions) in resistance‐trained individuals. Twenty‐two adults with more than 6 months resistance training experience were randomized to either the LOW or HIGH intervention group. Both groups completed an 8‐week training program consisting of four multi‐joint exercises targeting the hip and knee extensors. The program progressed from 12‐repetition maximum (RM) to 6‐RM, with 4–5 sets per exercise performed throughout the intervention. The four exercises were conducted either in one session or four sessions (one exercise per session) per week. 1‐RM in the squat, muscle thickness of the vastus lateralis, muscle mass of the lower body (measured using bioelectrical impedance), and jump height were assessed pre‐ and post‐intervention. The HIGH group demonstrated a statistically significant increase in 1‐RM compared to the LOW group (7 kg, p = 0.01), while no statistically significant differences were found between the groups for the other outcomes (p = 0.26–0.63). Both interventions resulted in statistically significant increases in 1‐RM squat (8 and 15 kg), muscle thickness (2.3 and 2.8 mm), and jump height (1.5 and 1.9 cm) from pre‐to post‐test. There were no statistical changes in lower‐body muscle mass for either group (p = 0.16–0.86). In conclusion, a weekly training protocol of four multi‐joint lower‐limb exercises distributed over four sessions resulted in greater increases in maximal strength compared to one session in resistance‐trained adults. Both frequencies were similarly effective in improving muscle hypertrophy and jump height.

Differences in Female Lift Quality During Back Squat, Bench Press, and Deadlift Compared to Standardized Percent of 1RM and Repetitions Allowed

The purpose of the study was to examine the difference between the current norm repetition-intensity recommendations and the performed repetitions of females at concurrent intensities. Females (n = 17) with six-months of consistent resistance training experience completed five testing sessions. Session-one consists of one-repetition maximum (1RM) testing for the squat (SQ), bench press (BP), and deadlift (DL). Sessions 2-5 involved repetition-maximum testing at 65, 75, 85, and 95% 1RM, in the order of SQ, BP, then DL, with 10-15 minutes of rest between exercises. A 3 (exercise) x 4 (percentage-intensity) Mixed Factorial ANOVA determined significant differences in repetitions performed between exercises at each intensity level. A series of one-sample t-tests were performed to indicate female differences between established target repetitions for each exercise across all intensities (65% = 15, 75% = 10, 85% = 6, 95% = 2). Significance level was set at p < .05. There was no significant main effect (p=0.14) between repetitions completed during SQ, BP, or DL at 65% (26.1±6.8, 21.3±6.8, 23.4±6.3, respectively), 75% (18.0±6.2, 14.4±4.2, 15.7±4.7, respectively), 85% (10.3±3.7, 9.0±4.6, 9.6±4.1, respectively), nor 95% 1RM (4.1±2.4, 2.5±2.0, 3.4±2.0, respectively). No significant difference was recognized (p = 0.09) between current norms and female BP repetitions at 95%. Significantly higher repetitions were completed by females at all other percentages during SQ, BP, and DL. These results suggest different resistance training intensity-repetition ratios should be prescribed for females in comparison to current norms; meriting future research aimed at establishing a sex-specific intensity-repetition ratio.

The Effect of Oral Adenosine Triphosphate (ATP) Supplementation on Anaerobic Exercise in Healthy Resistance-Trained Individuals: A Systematic Review and Meta-Analysis.

Adenosine triphosphate (ATP) is an energy and signaling molecule. It is synthesized endogenously and can be taken as an oral supplement. This review aimed to identify the effects of oral ATP supplementation on anaerobic exercise in healthy resistance-trained adults. A systematic review and meta-analysis were performed based on the Preferred Reporting Items of Systematic Reviews and Meta-Analysis (PRISMA) criteria. The inclusion criteria were articles published from 2000 to 2022, with anaerobic variables (maximal strength, maximum repetitions, and maximum anaerobic power) measurable in healthy adults with experience in resistance training, only randomized placebo-controlled clinical trials (RCTs), and with the acute (a single dose 30 min to 24 h before the tests) and/or chronic (>1 day) oral supplementation of ATP. A total of five RCTs with 121 adult men were included. The oral ATP supplementation achieved significantly greater gains in maximal strength compared with the placebo (PL) (MD = 8.13 kg, 95%CI [3.36-12.90], p < 0.001). Still, no differences were observed in the maximum number of repetitions or the maximum anaerobic power. Furthermore, 400 mg of ATP showed improvement in anaerobic exercise regardless of the duration of the supplementation protocol. In conclusion, supplementation with 400 mg of ATP doses can improve maximal muscle strength in resistance-trained men.

Effects of a portable, cable-based concentric-only resistance machine on muscular strength in untrained young adults

The purpose of this study was to investigate the effects of concentric-only resistance training in comparison to traditional concentric-eccentric resistance training on upper and lower body strength using a portable cable-based concentric-only resistance machine. Thirty-two participants (10 females, 22 males; mean age of 23.4 ± 2.0) with minimal resistance training experience exercised thrice weekly to complete a 12-week training program. Participants were blinded and randomly allocated 1:1 to an intervention group (n = 16, wherein the resistance training used the concentric-only machine (CRT)) or a control group (n = 16, wherein the resistance training was completed using traditional concentric-eccentric with a conventional cable-based machine (CON)). While both groups improved in 1-RM chest press and squat press performance, there was no significant difference between groups. These findings suggest that the use of a portable CRT machine may confer similar strength benefits in comparison to traditional concentric-eccentric training. It is possible that the lack of the eccentric component with the CRT machine enables for a higher training volume to be completed, which consequently results in strength benefits.

Resistance Training With Different Velocity Loss Thresholds Induce Similar Changes in Strength and Hypertrophy.

Andersen, V, Paulsen, G, Stien, N, Baarholm, M, Seynnes, O, and Saeterbakken, AH. Resistance training with different velocity loss thresholds induce similar changes in strengh and hypertrophy. J Strength Cond Res 38(3): e135-e142, 2024-The aim of this study was to compare the effects of 2 velocity-based resistance training programs when performing resistance training with matched training volume. Ten resistance-trained adults volunteered (age, 23 ± 4.3 years; body mass, 68 ± 8.9 kg; and height, 171 ± 8 cm) with a mean resistance training experience of 4.5 years. A within person, between leg design was used. For each subject, the legs were randomly assigned to either low velocity loss (LVL) threshold at 15% or high velocity loss (HVL) threshold at 30% velocity loss. Leg press and leg extension were trained unilaterally twice per week over a period of 9 weeks. Before and after the intervention, both legs were tested in 1 repetition maximum (RM) (kg), maximal voluntary contraction (MVC) (N), rate of force development (N·s -1 ), average velocity (m·s -1 ), and power output (W) at 30, 45, 60, and 75% of 1 RM (all in unilateral leg press). Furthermore, muscle thickness (mm) of the vastus lateralis and rectus femoris, pennation angle (°) of the vastus lateralis, and the fascicle length (mm) of the vastus lateralis were measured using ultrasound imaging. The data were analyzed using mixed-design analysis of variance. No differences between the legs in any of the variables were found; however, both low and HVL were effective for increasing 1 RM (ES = 1.25-1.82), MVC (effect size [ES] = 0.42-0.64), power output (ES = 0.31-0.86), and muscle thickness (ES = 0.24-0.51). In conclusion, performing velocity-based resistance training with low and HVL with equal training volume resulted in similar effects in maximal and explosive strength in addition to muscular adaptations.

Artificial intelligence in sport: Exploring the potential of using ChatGPT in resistance training prescription.

OpenAI's Chat Generative Pre-trained Transformer (ChatGPT) technology enables conversational interactions with applications across various fields, including sport. Here, ChatGPT's proficiency in designing a 12-week resistance training programme, following specific prompts, was investigated. GPT3.5 and GPT4.0 versions were requested to design 12-week resistance training programmes for male and female hypothetical subjects (20-years-old, no injury, and 'intermediate' resistance training experience). Subsequently, GPT4.0 was requested to design an 'advanced' training programme for the same profiles. The proposed training programmes were compared with established guidelines and literature (e.g., National Strength and Conditioning Association textbook), and discussed. ChatGPT suggested 12-week training programmes comprising three, 4-week phases, each with different objectives (e.g., hypertrophy/strength). GPT3.5 proposed a weekly frequency of ~3 sessions, load intensity of 70-85% of one repetition-maximum, repetition range of 4-8 (2-4 sets), and tempo of 2/0/2 (eccentric/pause/concentric/'pause'). GPT4.0 proposed intermediate- and advanced programme, with a frequency of 5 or 4 sessions, 60-90% or 70-95% intensity, 3-5 sets or 3-6 sets, 5-12 or 3-12 repetitions, respectively. GPT3.5 proposed rest intervals of 90-120 s, and exercise tempo of 2/0/2. GPT4.0 proposed 60-180 (intermediate) or 60-300 s (advanced), with exercise tempo of 2/1/2 for intermediates, and 3/0/1/0, 2/0/1/0, and 1/0/1/0 for advanced programmes. All derived programmes were objectively similar regardless of sex. ChatGPT generated training programmes which likely require additional fine-tuning before application. GPT4.0 synthesised more information than GPT3.5 in response to the prompt, and demonstrated recognition awareness of training experience (intermediate vs advanced). ChatGPT may serve as a complementary tool for writing 'draft' programme, but likely requires human expertise to maximise training programme effectiveness.

High-Intensity Conditioning Activity Causes Localized Postactivation Performance Enhancement and Nonlocalized Performance Reduction

Abstract Kolinger D, Stastny P, Pisz A, Krzysztofik M, Wilk M, Tsoukos A, and Bogdanis GC. High-intensity conditioning activity causes localized postactivation performance enhancement and nonlocalized performance reduction. J Strength Cond Res 38(1): e1–e7, 2024—This study aimed to examine whether a conditioning activity (CA) performed by the legs (barbell back squat) may cause postactivation performance enhancement (PAPE) on muscle groups other than leg extensors in isokinetic (eccentric [ECC] and concentric [CON]) and dynamic movement. Twelve male basketball players (age: 21.3 ± 3.2, body mass: 89.6 ± 14.1 kg, height: 187.4 ± 4.6 cm, and 1 repetition maximum (1RM) barbell back squat: 113 ± 21 kg) with previous resistance-training experience of at least 2 years, performed 3 sets of 3–4 repetitions of back-squats with submaximal load (60, 90, and 90% 1RM) as CA. Before and after the CA, they performed pretest and post-test in the form of countermovement jumps (CMJs) (localized) or explosive push-ups (EPUs) (nonlocalized) along with isokinetic flexion and extension at the knee (localized) or at the elbow (nonlocalized). The localized and nonlocalized protocols were divided into 2 days in a randomized order. The back squat as CA significantly increased peak torque (PT) (p &lt; 0.05) in all CON and ECC muscle actions and average power per repetition (APPR) (p &lt; 0.05) (all muscle actions except ECC flexion) of the localized isokinetic tests with large (&gt;0.8) and medium (0.4–0.79) effect sizes and significantly decreased (p &lt; 0.01) the PT and APPR (p &lt; 0.01) of the nonlocalized isokinetic test in the ECC flexion. The CMJ and EPU tests showed no significant differences (p &gt; 0.05) between premeasures and postmeasures of take-off height. The effect of PAPE seems to be specific to the muscles most involved in the CA, and the CA inhibits PT of subsequent muscle ECC contractions in muscles not involved in the CA.

Relationship Between Stance Width Variation During One Repetition Maximum Barbell Hip Thrust Performance and Kicking Speed for Young Elite Silat Athletes

Study purpose. This study aimed to determine the relationship between kicking speed performance and different stance widths during barbell hip thrust (BHT) at one repetition maximum (1RM) scores among young elite Silat athletes. Materials and methods. 15 male and 15 female Silat athletes with at least one year of resistance training experience and a mean age of 21.3 ± 1.2 years participated in this study. The load indicator performance associated with kicking performance was measured using 1RM load during BHT at varying stance widths. The data was analyzed using Pearson correlation tests through the SPSS Version 25 application. Results. A significant correlation was found between stance width, physical characteristics, and performance metrics with a low to moderate relationship. For physical features, weight (r=0.43, p&lt;.05), height (r= 0.64, p&lt;.05), and leg length (r= 0.44, p&lt;.05) show positive relationship. Low to moderate significant relationships were found during WSW-RFK (r=0.39, p&lt;.05) regarding 1RM and kicking performance. No significant correlations were found between NSW or NRW and the observed variables, except for a negative correlation between NRW and strength (r= -0.43, p &lt; .05). There was a significant difference between males vs. females in RFK-NSW, RFK (p=0.006, p&lt; .05), and LFK-NRW (p=0.001, p&lt; .05) in kicking performance. Conclusions. This study revealed that stance width in barbell hip thrusts moderately correlates with physical characteristics and performance in young elite Silat athletes, where wider stances align with physical characteristics and narrower stances align with lower kicking performance. It also highlighted the importance of personalized training due to observed gender differences in kicking speed.

A Single Dose of Microencapsulated Cocoa Supplementation Does Not Speed up Muscle Force Recovery after Eccentric Exercise-Induced Muscle Damage: A Placebo-Controlled, Double-Blind, Crossover Study

Exercise-induced muscle damage is associated with symptoms such as inflammation, delayed-onset muscle soreness, and impaired muscle performance. The intake of cocoa polyphenols has been suggested to improve muscle recovery due to their antioxidant and anti-inflammatory capacity. However, their bioavailability presents a challenge. Therefore, food microencapsulation may be an alternative to protect polyphenols, ensuring their biological effects. This study aimed to investigate the effect of a single dose of microencapsulated cocoa on the changes in muscle damage markers after eccentric exercise. In this randomized, double-blind, crossover study, fourteen healthy volunteers with previous resistance training experience performed 6 × 10 maximal isokinetic eccentric contractions of their elbow flexors using an isokinetic dynamometer after ingesting 25 g of microencapsulated cocoa or placebo. Peak isometric torque was measured using maximal voluntary isometric contractions, and pain was measured using a visual analogic scale both before and 24 h, 48 h, and 72 h after the damage protocol. Plasma glutathione and malondialdehyde levels were measured using high-performance liquid chromatography, and concentrations of myoglobin and C-reactive protein were determined using a fluorescence immunoassay analyzer. Significant decreases were seen in the peak isometric torque and pain measures from pre- to 72 h post-eccentric exercise. A significant main effect for time was found only for plasma myoglobin at 2 h, 48 h, and 72 h, and for C-reactive protein at 2 h, compared to the pre-eccentric exercise values. No significant time-treatment effects were observed (all p &gt; 0.05). This study demonstrated that microencapsulated cocoa cannot improve muscle recovery after eccentric exercise, at least when a single dose is consumed.

The Influence of Unstable Load and Traditional Free-Weight Back Squat Exercise on Subsequent Countermovement Jump Performance.

The purpose of the present study was to examine the effects of a back squat exercise with unstable load (UN) and traditional free-weight resistance (FWR) on subsequent countermovement jump (CMJ) performance. After familiarisation, thirteen physically active males with experience in resistance training visited the laboratory on two occasions during either experimental (UN) or control (FWR) conditions separated by at least 72 h. In both sessions, participants completed a task-specific warm-up routine followed by three maximum CMJs (pre-intervention; baseline) and a set of three repetitions of either UN or FWR back squat exercise at 85% 1-RM. During the UN condition, the unstable load was suspended from the bar with elastic bands and accounted for 15% of the total load. Post-intervention, three maximum CMJs were performed at 30 s, 4 min, 8 min and 12 min after the last repetition of the intervention. The highest CMJ for each participant was identified for each timepoint. No significant increases (p > 0.05) in jump height, peak concentric power, or peak rate of force development (RFD) were found after the FWR or UN conditions at any timepoint. The lack of improvements following both FWR and UN conditions may be a consequence of the low percentage of unstable load and the inclusion of a comprehensive task-specific warm-up. Further research is required to explore higher UN load percentages (>15%) and the chronic effects following the implementation of a resistance training programme.

Postactivation performance enhancement in the vertical jump using loads above or below the optimum-power load for a jump squat.

Postactivation performance enhancement (PAPE) is an acute response of increased muscle performance following a conditioning activity (CA), generally prescribed based on the percentage of a one-repetition maximum. However, it is unknown how the PAPE response is affected when the CA is performed near the optimum power zone. The purpose of this study was to examine PAPE using loads that were 20% above or below the optimum-power load (OPL). Fifteen recreationally trained subjects, with at least one-year resistance training experience participated in this study. First, the OPL for the JS was determined. Then, subjects performed two protocols in a counterbalanced order: 20% above (+20%OPL) or below (-20%OPL). To examine PAPE on performance, the vertical jump was performed prior to and seven times following each jump squat protocol, with a 2-min rest interval between trials. The two-way ANOVA revealed main effects for condition (F=4.978; P<0.001) for jump height and jump power (F=2.589; P=0.017), but post-hoc comparisons did not show differences. Between baseline and the best trial following each jump squat protocol, two-way ANOVA did not reveal main effects (F=3.048; P=0.103) or interactions (F=0.304; P=0.590). Paired t-tests did not show significant differences between conditions for relative changes in jump height (P=0.543) or jump power (P=0.233). This study revealed similar results between 20% above or below the OPL on subsequent vertical jump performance.

The Influence of Resistance Training Experience on the Efficacy of Motor Imagery for Acutely Increasing Corticospinal Excitability.

Both motor imagery and resistance-training enhance motor function and corticospinal excitability. We tested the hypothesis that young participants with significant resistance-training experience would show heightened corticospinal excitability during a single session of motor imagery training. Fifty-six participants (mean ± SD age = 22 ± 2 years) were divided into resistance-trained and untrained groups. Forty-one upper-body resistance trained (21 males, 20 females; mean ± SD relative one repetition maximum bench press = 0.922 ± 0.317 kg/kg) and 15 untrained (4 males, 11 females; mean ± SD relative one repetition maximum bench press = 0.566 ± 0.175 kg/kg) participants visited the laboratory on three separate occasions. The first visit served as the familiarization session. During visits 2 and 3, participants engaged in a hand/wrist motor imagery protocol or rested quietly (control condition) in a randomized order. Before and after the interventions, single-pulse transcranial magnetic stimulation (TMS) over the motor cortex was used to measure resting motor-evoked potential amplitude of the first dorsal interosseous muscle. Our main finding was that motor imagery acutely increased corticospinal excitability by ~64% (marginal means pre = 784.1 µV, post = 1246.6 µV; p < 0.001, d = 0.487). However, there was no evidence that the increase in corticospinal excitability was influenced by resistance-training experience. We suspect that our results may have been influenced by the specific nature of the motor imagery task. Our findings have important implications for motor imagery prescription and suggest that motor imagery training may be equally beneficial for both resistance-trained and untrained populations. This study was prospectively registered at ClinicalTrials.gov (Identifier: NCT03889548).

Analysis of Power Output During the Countermovement and Split-Squat Jump Across Loads and High-Volume Repetitions in Elite Athletes

The primary purpose of this study was to determine the rate of peak power (PP) loss during the countermovement jump (CMJ) and split-squat jump (SSJ) across various loads within a set of high repetitions. Eleven collegiate track and field athletes who had several years of resistance training experience and were trained in the two types of jumps completed the study. The participants completed a familiarization session and 2 data collection sessions. The CMJ and SSJ were completed in random order during session 1 and 2 separated by a minimum of 72 hours. Three loads using dumbbells took place in random order with each session including body weight only (BW0), body weight plus 15% (BW15) and body weight plus 30% BW(30) for the SSJ and BW(0), BW(25), and BW(50) for the CMJ. PP was determined using the PUSH 2.0 3D accelerometer worn at the waist, which was connected to an ipad app using Bluetooth. The participants completed 14 repetitions each set with 8 min rest between sets. Repetition 3 demonstrated the highest mean PP (PPmax) within the set. No significant decrease in PP was observed until repetition 6 (3.6% below PPmax) during the SSJ and repetition 8 (5.2% below PPmax) during the CMJ. These data indicate that 5 or less repetitions should be completed during the CMJ and 7 or less for the SSJ when training for PP. Using 10% reduction in PP as an effective level to train for power endurance, we recommend completing a minimum of 12 repetitions during the CMJ and a minimum of 10 repetitions for the SSJ.

Postsubmaximal Isometric Full Squat Jump Potentiation in Trained Men.

Koźlenia, D, and Domaradzki, J. Postsubmaximal isometric full squat jump potentiation in trained men. J Strength Cond Res 38(3): 459-464, 2024-This study investigated the effects of postsubmaximal isometric full squats on jump height (JH). The study included 45 men aged 20-27 years with at least 6 years of resistance training experience that had been continuous for at least 2 years and a minimum relative strength of 120% of body mass in the full-back squat. They were randomly divided into an experimental group (EG) and a control group (CG). After a standard warm-up, subjects performed a countermovement jump (CMJ) to ascertain a baseline value. A conditioning activity (CA) introduced in the EG involved three 4-second sets of a high bar isometric full-back squat at 70% repetition maximum, with a 1-minute break. Five CMJs were performed in the following 9 minutes. Statistical significance was set at α = 0.05. A 2-way analysis of covariance (ANCOVA) (group-time), with baseline CMJ as a covariable, revealed statistically significant differences between groups ( p < 0.0001). The Bonferroni post hoc tests revealed higher results in the EG at the third, fifth, seventh, and ninth minutes ( p < 0.05). A 1-way repeated-measures analysis of variance (ANOVA) showed that time was statistically significant within groups ( p < 0.0001). The post hoc tests indicated JH improvement after 3 minutes compared with the baseline, and the trend persisted in the following 6 minutes ( p < 0.05) in the EG. The postactivation performance enhancement (PAPE) protocol based on a submaximal isometric full squat enhanced JH in the third minute after CA, which persisted for at least 6 minutes. These results indicate a requirement to evoke performance enhancement in response to an isometric CA.

The Effect of Lifting Straps on Deadlift Performance in Females.

Trahey, KM, Lapp, EM, Talipan, TN, Guydan, TJ, Krupka, AJ, and Ellis, CE. The effect of lifting straps on deadlift performance in females. J Strength Cond Res 37(10): 1924-1928, 2023-Using lifting straps (LS) while deadlifting may increase the total number of repetitions performed and barbell velocity, and preserve grip strength; however, research in this area has only been conducted on men. This study investigated the effects of lifting straps on the total number of repetitions, mean and peak barbell velocity, and grip strength during the deadlift exercise in women. Ten women (20.1 ± 1.1 years; 165.4 ± 5.6 cm, 68.9 ± 10.3 kg) with 3.2 ± 2.1 years of resistance training experience participated in the study. After completing a 1-repetition maximum (1RM) test without LS, subjects completed 2 protocols: performing 3 sets of as many repetitions as possible of 80% 1RM with lifting straps (WS) and without lifting straps (NS). During both protocols, mean and peak barbell velocity were measured during each set, and grip strength was recorded before deadlifting and after each set. Repeated-measures analysis of variance were used to examine differences in the variables of interest, with an alpha level of 0.05 used to establish statistical significance. The WS condition allowed participants to perform significantly more reps while resulting in no statistically significant differences in mean or peak barbell velocity. The magnitude of grip strength loss was significantly lower during the WS condition. Results indicate that using LS while deadlifting allows women to perform more repetitions with greater preserved grip strength without negatively affecting barbell velocity. Thus, LS appear beneficial for deadlift performance in women and should be considered during resistance training involving the deadlift exercise.