Investigating the lumbar proprioception and core muscles recruitment pattern while getting up from a chair with weight lifting in patients with chronic functional constipation: cross-sectional study.

INTRODUCTION AND HYPOTHESIS: Patients with chronic functional constipation have some problems such as weakness of pelvic floor muscles, and a lack of coordination of pelvic floor and abdominal muscles has been seen. The goal of this study was to investigate the lumbar proprioception and the core muscle recruitment pattern. METHODS: The study type is a cross-sectional case-control study. There were 30 participants (case, n = 15, and control, n = 15). Electromyography of the core muscles was recorded while the subjects were getting up from the chair accompanied by lifting a weight, to check the pattern of muscle recruitment. Moreover, the lumbar proprioception was evaluated by an isokinetic device in both groups. The study was analyzed using independent t test and Mann-Whitney U test, and a nonparametric Friedman test was performed followed by Bonferroni pairwise comparison. RESULTS: The comparison of muscle activity delay between the two groups showed that there was a significant difference between the two groups regarding the abdominal muscles, anal sphincter, and erector spinae (p < 0.05). However, there was no significant difference in the rectus femoris and gluteal muscles between the two groups (p > 0.05). Moreover, the proprioception of the lumbar region showed a significant difference (p < 0.05) between the two groups. CONCLUSIONS: The results of this study demonstrated that the lumbar proprioception sense was reduced in the case group. This result can be justified, based on the problems in constipation (lack of coordination of muscles, weakness of pelvic floor muscles). The coordination of core muscles changed in patients with chronic functional constipation during a functional task.

Pelvic Floor Muscle Training on Stress Urinary Incontinence in Power- and Weightlifters: a Pilot Study.

INTRODUCTION AND HYPOTHESIS: Stress urinary incontinence (SUI) is defined as involuntary leakage of urine on physical effort and is prevalent among power- and weightlifters. However, there is scant knowledge on treatment options for this population. The aim of this pilot study was to evaluate the potential outcomes and feasibility of a pelvic floor muscle training (PFMT) program on SUI in nulliparous female power- and weightlifters. METHODS: This was a case-series study, including one weightlifter and two powerlifters aged 21-32 years. The participants conducted 12 weeks of PFMT at home, with weekly follow-up by a physiotherapist. Change in total score of the International Consensus of Incontinence Questionnaire Urinary Incontinence Short Form (ICIQ-UI-SF) was the primary outcome. Secondary outcome was perceived change assessed by the Patient Global Impression of Improvement (PGI-I) Scale and impact on sport participation. PFM strength, endurance, and resting pressure was measured using vaginal manometry. Feasibility was evaluated as adherence to training and self-efficacy (Self Efficacy Scale for Practicing Pelvic Floor Exercises). RESULTS: One athlete reduced their ICIQ-UI-SF score and experienced improvement in symptoms. One athlete reported no change, and one reported a worsening of symptoms. All three participants improved PFM strength and endurance, completed the testing, and 12 weeks of PFMT, but adherence varied between 40 and 80%. Participants reported a lack of time and energy and forgetting to perform the exercises, as reasons for low adherence. CONCLUSION: There were varying effects of a 12-week PFMT program on SUI in three strength athletes. The results can create the basis for a future randomized controlled trial.

Nutrition Practices of Lithuanian Elite International and National-level Male Bodybuilders in the Pre-competition Period.

OBJECTIVES: To compare the pre-competition nutrition practices of Lithuanian elite international-level (IL) and national-level (NL) bodybuilders. METHODS: Sixteen male bodybuilders (n=8 per group) were enrolled. The IL group comprised individuals achieving 1st to 4th place in the World and European Championships organized by the IFBB, whereas the NL group ranked between 1st and 6th place in the national championships. Body mass and diet data were obtained via a questionnaire. A repeated-measures ANOVA was performed using time as a within factor and group as a between factor. RESULTS: Both groups experienced a reduction in body mass during the pre-competition phase (p<0.001), which was slower in the IL than in the NL group (p=0.048). Both groups exhibited a reduction in caloric (p<0.001), carbohydrate (p<0.001), and fat (p=0.006) intake relative to body mass, but not in protein intake. Nevertheless, the IL group had a higher intake of calories (p=0.015), protein (p<0.001), but not carbohydrates relative to body mass vs. the NL group. CONCLUSIONS: The Lithuanian IL and NL bodybuilders both reduced calories by cutting fat and carbohydrates during pre-competition. The IL group maintained higher calorie and protein intake, resulting in similar body mass loss but at a slower rate than the NL group.

Neuromuscular Repatterning of the Pectoralis Major During the Bench Press Exercise Following a 10-week Targeted Resistance Training Intervention.

OBJECTIVE: The bench press is a resistance training exercise that targets several upper body muscles, including the pectoralis major (PM), anterior deltoid (AD), and triceps brachii (TB). The purpose of this study was to influence the PM activity pattern during the bench press after a 10-week targeted resistance training intervention. METHODS: Sixteen men with significant experience in strength training participated in this study. They were divided into two groups: experimental and control. The experimental group underwent targeted training of PM and bench press, while the control group only did bench press. Electromyography (EMG) was used to assess muscle activity before and after the intervention. RESULTS: The experimental group had a significant increase in PM activity after the intervention (p=0.0002; ES=2.6), while the control group did not show any significant change (p=0.14). The activity of AD and TB remained relatively stable across both groups and time points. CONCLUSIONS: These findings indicate that focused resistance training can improve PM involvement in the bench press, potentially optimizing muscle excitation patterns and performance.

The effect of anabolic androgenic steroids on heart rate recovery index and electrocardiographic parameters in male bodybuilders.

BACKGROUND: The control of the cardiovascular system depends on the autonomic nerve system. Chronic anabolic andorogenic steroids (AAS) use causes sympathovagal imbalance and increases sympathetic nerve activity. OBJECTIVE: The reduction in heart rate from the peak exercise rate following the end of the exercise stress test is known as the heart rate recovery index (HRRI). Several methods have been utilized to assess myocardial repolarization, such as QT interval (QT), corrected QT interval (QTc), and T-wave peak-to-end interval (Tp-e interval). Based on a growing number of data a higher Tp-e/QT ratio is linked to malignant ventricular arrhythmias, and an increased Tp-e interval may correlate with the transmural dispersion of repolarization. Our hypothesis is that the use of chronic AAS was decrease HRRI during maximal exercise and increased risk of cardiac arrhythmias and sudden cardiac death. METHODS: This study included 44 male bodybuilders, with an average age of 29.7 ± 8.14 years, divided into AAS abuse [AAS users (n = 21) and AAS nonuser (n = 23)]. RESULTS: The first (p = 0.001) and second minute (p = 0.001) HRRI of the subjects with AAS users were significantly lower than those of the control group. Additionally, HRRI after the third (p = 0.004) and fifth minutes (p = 0.007) of the recovery period were significantly lower in AAS group compared with the control group. Who used AAS had significantly higher QT, QTc, Tp-e, Tp-e/QT, and Tp-e/QTc values than non-users (all p = 0.001). CONCLUSIONS: Chronic AAS use has been shown to cause sympathetic dominance, which may be a pro arrhythmic state.

Para Powerlifting Performance: A Systematic Review.

This research aimed to conduct a systematic review of para powerlifting strength performance. The searches were conducted in three electronic databases: PubMed, Scopus, and SPORTDiscus. Intervention studies related to para powerlifting performance were included. The main information was extracted systematically, based on criteria established by the authors. The data on study design, sample size, participant's characteristics (e. g. type of disability, sex, age, body weight, and height), training experience, assessment tools, physical performance criteria, and force-related outcomes were extracted and analyzed. The studies (n=9) describe factors related to biomechanics and performance. Outcomes revealed that the one-repetition maximum test is used as load prescription and that para powerlifting should work at high speeds and higher loads. Regarding technique, grip width with 1.5 biacromial distance provides a good lift and partial amplitude training as an alternative to training. There are no differences in total load and movement quality in the lumbar arched technique compared with the flat technique. As a monitoring method, repetitions in reserve scale was used for submaximal loads. Finally, our outcomes and discussion indicated strategies and techniques that can be used by para powerlifting coaches.

Sex and Equipment Impact on Lifting Velocity and the Maximum Repetitions in Bench Press.

This study investigated how equipment and sex affect the prediction accuracy of the maximum number of repetitions performed to failure (RTF) using the fastest mean velocity of the set (MVfastest). Sixteen men and twelve women completed four sessions (two using free-weight equipment and two sessions using the Smith machine). Each session involved three sets of repetitions to failure against the 65%, 75%, and 85% of the one-repetition maximum, interspersed by 10-min of rest. The goodness-of-fit of the individualized RTF-MVfastest relationships was comparable between both equipment types and sexes (P≥0.510). Moreover, there were not significant differences in the MVfastest associated with RTF between equipment types (P≥0.258). However, the MVfastest associated with RTF was higher for men than for women in repetitions 6 to 15 (P≤0.043; ES≥0.69). In addition, the absolute errors when predicting RTF showed no significant differences between equipment types and loads (P<0.444). Specifically, these RTF estimates were within an acceptable range for men (<2 repetitions), but not for women (≥2 repetitions) (main effect of sex: P≤0.018; ES≥0.58). These findings suggest that individualized RTF-MVfastest equations estimate the RTF with an acceptable precision in men during bench press exercises in both equipment types but exhibit lower precision for women.

Effects of Eccentric Phase Velocity on Bench Press Concentric Bar Velocity in the Young and Elderly.

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

Resistance Training Intensity Prescription Methods Based on Lifting Velocity Monitoring.

Resistance training intensity is commonly quantified as the load lifted relative to an individual's maximal dynamic strength. This approach, known as percent-based training, necessitates evaluating the one-repetition maximum (1RM) for the core exercises incorporated in a resistance training program. However, a major limitation of rigid percent-based training lies in the demanding nature of directly testing the 1RM from technical, physical, and psychological perspectives. A potential solution that has gained popularity in the last two decades to facilitate the implementation of percent-based training involves the estimation of the 1RM by recording the lifting velocity against submaximal loads. This review examines the three main methods for prescribing relative loads (%1RM) based on lifting velocity monitoring: (i) velocity zones, (ii) generalized load-velocity relationships, and (iii) individualized load-velocity relationships. The article concludes by discussing a number of factors that should be considered for simplifying the testing procedures while maintaining the accuracy of individualized L-V relationships to predict the 1RM and establish the resultant individualized %1RM-velocity relationship: (i) exercise selection, (ii) type of velocity variable, (iii) regression model, (iv) number of loads, (v) location of experimental points on the load-velocity relationship, (vi) minimal velocity threshold, (vii) provision of velocity feedback, and (viii) velocity monitoring device.

Inter-repetition Rest Impact on Percentage of Repetition Completed at Certain Velocity Loss.

This study examined the impact of different inter-repetition rest (IRR) configurations (zero seconds [IRR0], three seconds [IRR3], and self-selected less than five seconds [SSIRR]) on estimating the number of repetitions (Nrep) and the percentage of completed repetitions relative to the maximum number of repetitions possible to failure (%rep) after reaching 10%, 20%, and 30% velocity loss thresholds (VLT). Eighteen men completed three sessions, each with a different IRR configuration, separated by 48-72 hours. Single sets of repetitions to momentary muscular failure were performed against 65%, 75%, and 85% of the one-repetition maximum during free-weight back squat and bench press exercises. No significant differences were reported between IRR configurations for the Nrep (P≥0.089) and %rep (P≥0.061), except for %rep after reaching the 20-30%VLT against 65%1RM and the 10-20%VLT against 75%1RM in the bench press exercise (P≤0.048). Additionally, both Nrep and %rep exhibited high interindividual variability (between-subject CV=14-79%) across the different IRR configurations. The individual %rep-%VLT relationships were slightly stronger than the general %rep-%VLT relationships (median R 2 =0.914-0.971 vs. 0.698-0.900). Overall, regardless of the IRR configuration, this novel velocity-based approach does not guarantee the same effort levels across subjects in the free-weight back squat and bench press sets.

Examining Unilateral and Bilateral Exercises through the Load-velocity Relationship.

This study aimed to examine the load-velocity (L-V) relationship in the bench-press (BP) and leg-press (LP) exercises performed unilaterally, and compared this unilateral L-V relationship with the bilateral variants. Nineteen men (age=23.5±2.1 years) completed two incremental tests in BP and LP, performed bilaterally and unilaterally, across two sessions with a 48-hour rest period. We found a close relationship between medium propulsive velocity (MPV) and %1RM in unilateral BP (R2 =0.97, SEE=0.06 m·s-1) and LP (R2=0.96, SEE=0.06 m·s-1). No significant differences were observed between the preferred and non-preferred sides in the L-V relationship for either exercise. Additionally, higher velocities were achieved in unilateral exercises compared to bilateral exercises, particularly with light and moderate loads (30-70%1RM) in BP (p<0.05) and with light loads (30-45%1RM) in LP (p<0.05). Close L-V relationships were observed in unilateral exercises, without differences in the L-V relationships between preferred and non-preferred sides despite the interlimb asymmetries in the absolute strength values. Interestingly, lower velocities were observed at light loads (~30-45% 1RM) for bilateral compared to unilateral exercises, which could be explained by different strength deficits for these exercises.

Effects of Different Weekly Set Volumes on Strength and Perceptual Responses in Athletes.

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

Load-velocity Relationship of the Bench Press Exercise is not Affected by Breast Cancer Surgery and Adjuvant Therapy.

We examined the effect of breast cancer surgery and adjuvant therapy on the relationship between bar velocity and relative intensity (load-velocity [L-V] relationship) of the bench press (BP) exercise. Twenty-two breast cancer survivors (age: 48.0±8.2 yr., relative strength: 0.40±0.08) completed a loading test up to the one-repetition maximum (1RM) in the BP using a lightweight carbon bar. General and individual relationships between relative intensity (%1RM) and mean propulsive velocity (MPV) were studied. Furthermore, the mean test velocity (MPVTest) and velocity attained to the 1RM (MPV1RM) were analyzed. These procedures and analyses were also conducted in 22 healthy women (age: 47.8±7.1 yr., relative strength: 0.41±0.09) to examine the differences in velocity parameters derived from these L-V relationships. Polynomial regressions showed very close relationships (R2≥0.965) and reduced estimation errors (≤4.9% 1RM) for both groups. Between-group differences in MPV attained to each %1RM were small (≤0.01 m·s-1) and not significant (p≥0.685). Similarly, the MPVTest (0.59±0.06 m·s-1) and MPV1RM (0.17±0.03 m·s-1) were identical for breast cancer survivors and healthy women. These results suggest that practitioners could use the same velocity parameters derived from the BP L-V relationship to prescribe this exercise in middle-aged women, regardless of whether they have suffered from breast cancer.

Sex-related differences in the load-velocity and load-power relationships of the decline bench press exercise.

The purpose of this study was to analyse the load-velocity and load-power relationships of the decline bench press exercise (DBPE) and to compare sex-related differences. Twelve young healthy men and women performed a progressive loading test for the determination of 1RM strength and individual load-velocity and load-power relationship in the DBPE. A very close relationship between mean propulsive velocity (MPV) and %1RM was observed (R2 = 0.94). This relationship improved when plotting data separately by sex (R2 = 0.96-97). Individual load-velocity profiles gave an R2 = 0.99 ± 0.01. The relationship between mean propulsive power (MPP) and %1RM was R2 = 0.23. When separating data by sex, R2 = 0.64-73 were obtained. Individual load-power profiles gave an R2 of 0.93 ± 0.07. Significant sex-related differences were found for MPV, with males having faster velocities than females from 30% to 40% 1RM (p = 0.01) and for MPP, with males having greater MPP (W) than females from 30% to 95% 1RM (p < 0.001). The results of this study show that a strong correlation exists between relative load and MPV/MPP in the DBPE, allowing the possibility of using one to predict the other with great precision, especially when a sex-specific equation is used.

The effects of anti-doping measures on sports performance in weightlifting.

BACKGROUND: Evaluating anti-doping measures is essential to optimise their effectiveness. Comparing sporting results that have a higher doping prevalence, such as weightlifting, before and after the implementation of anti-doping measures may serve as an effectiveness indicator. METHODS: The results of the most successful weightlifters of both sexes in two time periods, 2009-2015 and 2016-2022 were analysed. The Sinclair Total (ST) to compare the relative strength of weightlifters from different weight categories was calculated. RESULTS: A significant decrease in the ST during 2016-2022 (p < 0.001) in athletes of all ages and both sexes overall was reported. When analysed by age, there was a decrease in ST in juniors and seniors of both sexes (p = 0.010 and p < 0.001, respectively), but not in youth. There was a decrease in the ST in senior men (p < 0.001), junior women (p < 0.001) and senior women (p < 0.001). CONCLUSION: In elite weightlifting, adult athletic results declined during 2016-2022, which may partly be explained by the implementation of new methods to detect long-term anabolic androgenic steroid metabolites as well as other policies. This may highlight the effectiveness of these methods both in the prevention and detection of anti-doping rule violations.

A National 20-year Analysis of Weight Lifting-related Injuries and Fractures Among Adolescents.

BACKGROUND: Increasing strength through weightlifting has become a core component of competitive sports training, recreational exercise programs, and school physical education classes. Although many health benefits exist, there is concern for injury, especially with improper supervision and accelerated progression of training loads. Though organizations have advocated safe training practices, trends in the national health burden of injuries, specifically fractures, associated with weightlifting in the adolescent population have not been investigated. METHODS: The National Electronic Injury Surveillance System database was queried between 2002 and 2021 for patients aged 11 to 21 years presenting to US Emergency Departments with weight lifting-related injuries. The narrative component of each case identified was analyzed to include only patients noted to be using weightlifting equipment or free weights at the time of injury. Estimates and analyses were performed with 95% CIs. RESULTS: Although there has been some variability in weight lifting-related injuries, the incidence remained roughly constant over the 20 years ( R2 =0.0364). 14,497 cases were identified, reflecting a national estimate of 540,986 total injuries and an annual estimate of 27,049 injuries. Most injuries occurred among 15-to-18-year olds (44.1%±1.6%) and 19-to-21-year olds (38.3%±2.0%). The most common injuries were sprain/strain (36.7%±1.3%), contusion/abrasion (15.7%±0.7%), and fracture (9.9%±0.3%). There were 53,813 estimated fractures, giving an annual incidence of 2,691 fractures. As a portion of all injuries, the number of fractures decreased significantly as patients got older, accounting for 26.8%±3.3% at age 11 and only 8.3%±0.9% at age 21 ( R2 =0.6626). Fingers (37.1%±1.8%) and toes (27.9%±1.4%) were the most fractured body parts. Overall, fractures mainly occurred either at school (25.3%±2.0%) or places of recreation (24.7%±2.2%). CONCLUSIONS: Despite the guidelines to improve safety, the national health burden of weight lifting-related injuries among adolescents has remained constant over the past 20 years. Given that most of the fractures occur in the distal extremities, such as toes and fingers, at school and places of recreation, there may be an opportunity to promote safer weightlifting practices and the development of weightlifting equipment with in-built safety mechanisms, especially at gyms and schools. LEVEL OF EVIDENCE: Level III-prognostic.

Becoming a World Champion Powerlifter at 71 Years of Age: It Is Never Too Late to Start Exercising.

This case study assessed body composition, muscle strength, cardiorespiratory fitness, and metabolic health of the present female world champion powerlifter in the 70+ age category who started resistance exercise training at 63 years of age with no prior experience with structured exercise training. Measures of body composition (magnetic resonance imaging, computed tomography, and dual-energy X-ray absorptiometry scanning, leg volume); strength (one-repetition maximum leg press and extension, maximum voluntary contraction, and handgrip strength); physical function (short physical performance battery); cardiorespiratory fitness (peak oxygen consumption); and metabolic health (oral glucose tolerance test) were assessed. In addition, a muscle biopsy was collected to assess muscle fiber type distribution and cross-sectional area (CSA). Where possible, data were compared with previously (un)published sex- and age-matched data using z scores. Skeletal muscle mass index was calculated by dividing limb muscle mass by height squared. Data from the control groups are expressed as mean ± 95% confidence interval. Our participant (age: 71 years; body mass: 64.5 kg; body mass index: 27.6 kg/m2) reported a good bone mineral density of 1.09 g/cm2 (T score between -1 and +1) and very low values of abdominal and organ body fat (i.e., between 20% and 70% lower compared with a reference group of postmenopausal women). In addition, she showed a 33% greater skeletal muscle mass index when compared with healthy, older female control subjects (7.9 vs. 5.9 [5.7-6.2] kg/m2; n = 61) as well as 37% greater muscle quadriceps CSA (63.8 vs. 46.6 [44.5-48.7] cm2; n = 48) and 46% greater Type II muscle fiber CSA (4,536 vs. 3,097 [2,707-3,488] µm2; n = 19). Absolute leg press muscle strength was 36% greater (190 vs. 140 [132-147] kg; n = 30) and handgrip strength was 33% greater (33 vs. 25 [23-26] kg; n = 48) when compared with healthy, age-matched controls. In conclusion, even for resistance exercise naïve individuals, starting exercise at an advanced age can lead to improvements in body composition and muscle strength allowing older adults to reduce the risk for developing metabolic syndrome, live independently, and even compete at a world class level.

Comparing Video Analysis to Computerized Detection of Limb Position for the Diagnosis of Movement Control during Back Squat Exercise with Overload.

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

Prediction of One Repetition Maximum in Free-Weight Back Squat Using a Mixed Approach: The Combination of the Individual Load-Velocity Profile and Generalized Equations.

ABSTRACT: Fitas, A, Santos, P, Gomes, M, Pezarat-Correia, P, Schoenfeld, BJ, and Mendonca, GV. Prediction of one repetition maximum in free-weight back squat using a mixed approach: the combination of the individual load-velocity profile and generalized equations. J Strength Cond Res 38(2): 228-235, 2024-We aimed to develop a mixed methods approach for 1 repetition maximum (1RM) prediction based on the development of generalized equations and the individual load-velocity profile (LVP), and to explore the validity of such equations for 1RM prediction. Fifty-seven young men volunteered to participate. The submaximal load-velocity relationship was obtained for the free-weight parallel back squat. The estimated load at 0 velocity (LD0) was used as a single predictor, and in combination with the slope of the individual LVP, to develop equations predictive of 1RM. Prediction accuracy was determined through the mean absolute percent error and Bland-Altman plots. LD0 was predictive of 1RM ( p < 0.0001), explaining 70.2% of its variance. Adding the slope of the LVP to the model increased the prediction power of 1RM to 84.4% ( p < 0.0001). The absolute percent error between actual and predicted 1RM was lower for the predictions combining LD0 and slope (6.9 vs. 9.6%). The mean difference between actual and estimated 1RM was nearly zero and showed heteroscedasticity for the LD0 model, but not for the combined model. The limits of agreement error were of 31.9 and 23.5 kg for LD0 and LD0 combined with slope, respectively. In conclusion, the slope of the individual LVP adds predictive value to LD0 in 1RM estimation on a group level and avoids error trends in the estimation of 1RM over the entire spectrum of muscle strength. However, the use of mixed methods does not reach acceptable accuracy for 1RM prediction of the free-weight back squat on an individual basis.

Can the Velocity of a 1RM Hang Power Clean Be Used to Estimate a 1RM Hang High Pull?

ABSTRACT: Suchomel, TJ, Techmanski, BS, Kissick, CR, and Comfort, P. Can the velocity of a 1RM hang power clean be used to estimate a 1RM hang high pull? J Strength Cond Res 38(7): 1321-1325, 2024-The purpose of this study was to estimate the 1-repetition maximum hang high pull (1RM HHP) using the peak barbell velocity of a 1RM hang power clean (HPC). Fifteen resistance-trained men (age = 25.5 ± 4.5 years, body mass = 88.3 ± 15.4 kg, height = 176.1 ± 8.5 cm, relative 1RM HPC = 1.3 ± 0.2 kg·kg-1) with previous HPC experience participated in 2 testing sessions that included performing a 1RM HPC and HHP repetitions with 20, 40, 60, and 80% of their 1RM HPC. Peak barbell velocity was measured using a linear position transducer during the 1RM HPC and HHP repetitions performed at each load. The peak barbell velocity achieved during the 1RM HPC was determined as the criterion value for a 1RM performance. Subject-specific linear regression analyses were completed using slope-intercept equations created from the peak velocity of the 1RM HPC and the peak barbell velocities produced at each load during the HHP repetitions. The peak barbell velocity during the 1RM HPC was 1.74 ± 0.30 m·s-1. The average load-velocity profile showed that the estimated 1RM HHP of the subjects was 98.0 ± 19.3% of the 1RM HPC. Although a 1RM HHP value may be estimated using the peak barbell velocity during the HPC, strength and conditioning practitioners should avoid this method because of the considerable variation within the measurement. Additional research examining different methods of load prescription for weightlifting pulling derivatives is needed.