Linear Position Transducer Research Articles

Valid and Reliable Barbell Velocity Estimation Using an Inertial Measurement Unit.

The accurate assessment of the mean concentric barbell velocity (MCV) and its displacement are crucial aspects of resistance training. Therefore, the validity and reliability indicators of an easy-to-use inertial measurement unit (VmaxPro®) were examined. Nineteen trained males (23.1 ± 3.2 years, 1.78 ± 0.08 m, 75.8 ± 9.8 kg; Squat 1-Repetition maximum (1RM): 114.8 ± 24.5 kg) performed squats and hip thrusts (3–5 sets, 30 repetitions total, 75% 1RM) on two separate days. The MCV and displacement were simultaneously measured using VmaxPro® and a linear position transducer (Speed4Lift®). Good to excellent intraclass correlation coefficients (0.91 < ICC < 0.96) with a small systematic bias (p < 0.001; ηp2 < 0.50) for squats (0.01 ± 0.04 m·s−1) and hip thrusts (0.01 ± 0.05 m·s−1) and a low limit of agreement (LoA < 0.12 m·s−1) indicated an acceptable validity. The within- and between-day reliability of the MCV revealed good ICCs (0.55 < ICC < 0.91) and a low LoA (<0.16 m·s−1). Although the displacement revealed a systematic bias during squats (p < 0.001; ηp2 < 0.10; 3.4 ± 3.4 cm), no bias was detectable during hip thrusts (p = 0.784; ηp2 < 0.001; 0.3 ± 3.3 cm). The displacement showed moderate to good ICCs (0.43 to 0.95) but a high LoA (7.8 to 10.7 cm) for the validity and (within- and between-day) reliability of squats and hip thrusts. The VmaxPro® is considered to be a valid and reliable tool for the MCV assessment.

Validation of a Smartwatch-Based Workout Analysis Application in Exercise Recognition, Repetition Count and Prediction of 1RM in the Strength Training-Specific Setting.

The goal of this study was to assess the validity, reliability and accuracy of a smartwatch-based workout analysis application in exercise recognition, repetition count and One Repetition Maximum (1RM) prediction in the strength training-specific setting. Thirty recreationally trained athletes performed four consecutive sets of barbell deadlift, barbell bench press and barbell back squat exercises with increasing loads from 60% to 80% of their estimated 1RM with maximum lift velocity. Data was measured using an Apple Watch Sport and instantaneously analyzed using an iOS workout analysis application called StrengthControl. The accuracies in exercise recognition and repetition count, as well as the reliability in predicting 1RM, were statistically analyzed and compared. The correct strength exercise was recognised in 88.4% of all the performed sets (N = 363) with accurate repetition count for the barbell back squat (p = 0.68) and the barbell deadlift (p = 0.09); however, repetition count for the barbell bench press was poor (p = 0.01). Only 8.9% of attempts to predict 1RM using the StrengthControl app were successful, with failed attempts being due to technical difficulties and time lag in data transfer. Using data from a linear position transducer instead, significantly different 1RM estimates were obtained when analysing repetition to failure versus load-velocity relationships. The present results provide new perspectives on the applicability of smartwatch-based strength training monitoring to improve athlete performance.

Effects of FFP2/N95 face mask on low- and high-load resistance exercise performance in recreational weight lifters

ABSTRACT The objective of this study was to verify the acute effects of an FFP2/N95 face mask on moderate- and high-load resistance exercise performance in recreational weight lifters. Seventeen recreational weight lifters performed four randomized bouts: high intensity [70% of one maximum repetition (1RM)] and moderate intensity (50% 1RM), both with and without an FFP2/N95 face mask. All sequences of exercises were performed over four sets in the bench press exercise, performed on a Smith machine until movement failure, with two minutes of recovery between sets. A linear position transducer was used to measure the bar velocity, and record the mean propulsive velocity (MPV) and maximum propulsive velocity (V max). The rate of perceived effort (RPE), heart rate (HR), blood pressure, and oxygen saturation (SpO2) were recorded. For the high-intensity condition, MPV (p = 0.021) and V max (p = 0.004) were significantly lower in the mask condition compared to non-mask in set-1, however, there were no significant differences for moderate intensity or for total volume in either intensity (p > 0.05). There was a significant difference between conditions, with lower SpO2 (p = 0.010) and higher RPE (p = 0.008) when wearing the face mask only at the moderate intensity. In conclusion, the FFP2/N95 face mask impacted performance in the high-intensity resistance bench press exercise until movement failure but decreased oxygen saturation and increased rate of perceived effort only in the moderate-intensity exercise in recreational weight lifters. COVID-19 pandemic, has led to several countries adopting the use of masks in public spaces. Mask used during physical exercise it may induce early fatigue. However, despite the results with aerobic exercise, as far as we know, no studies have been carried out on wearing a mask during resistance exercise. This randomized, crossover study verified the acute effect of an FFP2/N95 face mask on moderate- and high-load upper body resistance exercise performance in recreational weight lifters. The FFP2/N95 face mask impacted performance, evaluated with bar velocity, in the high-intensity resistance bench press exercise until movement failure but decreased oxygen saturation and increased rate of perceived effort only in the moderate-intensity exercise.

Effects of Short-Term Golden Root Extract (Rhodiola rosea) Supplementation on Resistance Exercise Performance.

The purpose of this study was to examine the effects of short-term Golden Root Extract (GRE; Rhodiola rosea) supplementation on blood lactate, catecholamines, and performance during repeated bench press exercise. Resistance-trained males (n = 10) participated in this study. In a double-blinded, crossover, counterbalanced study design, participants supplemented with either 1500 mg/day of GRE or placebo (PL; gluten-free cornstarch) for 3 days prior to experimentation. An additional 500 mg dose was ingested 30 min prior to exercise testing. During each exercise trial, participants completed 2 repetitions of bench press at 75% of one-repetition maximum (1RM) as explosively as possible. A linear position transducer was used to measure mean concentric velocity. After 5 min of rest, participants completed 3 sets × repetitions to failure (RTF) at 75% 1RM separated by 2 min of rest between each set. A capillary blood sample was obtained pre- (PRE) and immediately post- (POST) exercise to measure blood concentrations lactate (LA), epinephrine (EPI), and norepinephrine (NE). Mean concentric velocity was significantly higher with GRE when compared to PL (p = 0.046). However, total RTF were significantly lower with GRE versus PL (p < 0.001). Regardless of treatment, LA was significantly higher Post versus Pre (p < 0.001), but GRE resulted in greater Post values compared to PL (p = 0.049). EPI and NE increased in both conditions Pre to Post (p < 0.001). However, Pre NE was significantly higher with GRE versus PL (p = 0.008). Findings indicate that short-term GRE supplementation increases mean bench press velocity but decreases bench press repetition volume. Furthermore, GRE resulted in higher NE levels and blood lactate following exercise. Thus, supplementing with GRE may enhance explosive resistance training performance but may also impair upper body strength-endurance.

Effect of Set-Structure on Upper-Body Muscular Hypertrophy and Performance in Recreationally-Trained Male and Female.

Davies, TB, Halaki, M, Orr, R, Mitchell, L, Helms, ER, Clarke, J, and Hackett, DA. Effect of set structure on upper-body muscular hypertrophy and performance in recreationally trained men and women. J Strength Cond Res 36(8): 2176-2185, 2022-This study explored the effect of volume-equated traditional-set and cluster-set structures on muscular hypertrophy and performance after high-load resistance training manipulating the bench press exercise. Twenty-one recreationally trained subjects (12 men and 9 women) performed a 3-week familiarization phase and were then randomized into one of two 8-week upper-body and lower-body split programs occurring over 3 and then progressing to 4 sessions per week. Subjects performed 4 sets of 5 repetitions at 85% one repetition maximum (1RM) using a traditional-set structure (TRAD, n = 10), which involved 5 minutes of interset rest only, or a cluster-set structure, which included 30-second inter-repetition rest and 3 minutes of interset rest (CLUS, n = 11). A 1RM bench press, repetitions to failure at 70% 1RM, regional muscle thickness, and dual-energy x-ray absorptiometry were used to estimate changes in muscular strength, local muscular endurance, regional muscular hypertrophy, and body composition, respectively. Velocity loss was assessed using a linear position transducer at the intervention midpoint. TRAD demonstrated a significantly greater velocity loss magnitude (g = 1.50) and muscle thickness of the proximal pectoralis major (g = -0.34) compared with CLUS. There were no significant differences between groups for the remaining outcomes, although a small effect size favoring TRAD was observed for the middle region of the pectoralis major (g = -0.25). It seems that the greater velocity losses during sets observed in traditional-set compared with cluster-set structures may promote superior muscular hypertrophy within specific regions of the pectoralis major in recreationally trained subjects.

Effect of Set-Structure on Upper-Body Muscular Hypertrophy and Performance in Recreationally-Trained Male and Female.

Davies, TB, Halaki, M, Orr, R, Mitchell, L, Helms, ER, Clarke, J, and Hackett, DA. Effect of set structure on upper-body muscular hypertrophy and performance in recreationally trained men and women. J Strength Cond Res XX(X): 000-000, 2021-This study explored the effect of volume-equated traditional-set and cluster-set structures on muscular hypertrophy and performance after high-load resistance training manipulating the bench press exercise. Twenty-one recreationally trained subjects (12 men and 9 women) performed a 3-week familiarization phase and were then randomized into one of two 8-week upper-body and lower-body split programs occurring over 3 and then progressing to 4 sessions per week. Subjects performed 4 sets of 5 repetitions at 85% one repetition maximum (1RM) using a traditional-set structure (TRAD, n = 10), which involved 5 minutes of interset rest only, or a cluster-set structure, which included 30-second inter-repetition rest and 3 minutes of interset rest (CLUS, n = 11). A 1RM bench press, repetitions to failure at 70% 1RM, regional muscle thickness, and dual-energy x-ray absorptiometry were used to estimate changes in muscular strength, local muscular endurance, regional muscular hypertrophy, and body composition, respectively. Velocity loss was assessed using a linear position transducer at the intervention midpoint. TRAD demonstrated a significantly greater velocity loss magnitude (g = 1.50) and muscle thickness of the proximal pectoralis major (g = -0.34) compared with CLUS. There were no significant differences between groups for the remaining outcomes, although a small effect size favoring TRAD was observed for the middle region of the pectoralis major (g = -0.25). It seems that the greater velocity losses during sets observed in traditional-set compared with cluster-set structures may promote superior muscular hypertrophy within specific regions of the pectoralis major in recreationally trained subjects.

Assessment of Back-Squat Performance at Submaximal Loads: Is the Reliability Affected by the Variable, Exercise Technique, or Repetition Criterion?

This study aimed to compare the between-session reliability of different performance variables during 2 variants of the Smith machine back-squat exercise. Twenty-six male wrestlers performed 5 testing sessions (a 1-repetition maximum [1RM] session, and 4 experimental sessions [2 with the pause and 2 with the rebound technique]). Each experimental session consisted of performing 3 repetitions against 5 loads (45–55–65–75–85% of the 1RM). Mean velocity (MV), mean power (MP), peak velocity (PV), and peak power (PP) variables were recorded by a linear position transducer (GymAware PowerTool). The best and average scores of the 3 repetitions were considered for statistical analyses. The coefficient of variation (CV) ranged from 3.89% (best PV score at 55% 1 RM using the pause technique) to 10.29% (average PP score at 85% 1 RM using the rebound technique). PP showed a lower reliability than MV, MP, and PV (CVratio ≥ 1.26). The reliability was comparable between the exercise techniques (CVratio = 1.08) and between the best and average scores (CVratio = 1.04). These results discourage the use of PP to assess back-squat performance at submaximal loads. The remaining variables (MV, MP, or PV), exercise techniques (pause or rebound), and repetition criteria (best score or average score) can be indistinctly used due to their acceptable and comparable reliability.

Effects of Acute Caffeine Intake on Power Output and Movement Velocity During a Multiple-Set Bench Press Exercise Among Mild Caffeine Users.

The main goal of this study was to evaluate the effectiveness of an acute dose of caffeine (6 mg/kg body mass (b.m.)) on power output and bar velocity during a bench press multiple-set resistance training session in participants with mild daily caffeine consumption (in the range of 1 to 3 mg/kg/b.m). Thirteen recreationally active male participants (age: 21.9 ± 1.2 years, body mass: 74.4 ± 5.3 kg, body mass index: 23.1 ± 1.6 kg/m2, bench press onerepetition maximum (1RM): 79.2 ± 14.9 kg), with daily caffeine ingestion of 1.56 ± 0.56 mg/kg/b.m., participated in the study with a randomized double-blind experimental design. Each participant performed two identical experimental sessions, 60 min after the intake of a placebo (PLAC) or 6 mg/kg/b.m. of caffeine (CAF-6). In each experimental session, participants performed 5 sets of 5 repetitions of the bench press exercise with a load equivalent to 70% 1RM. The eccentric and concentric phases of the bench press exercise were performed at maximal possible velocity in each repetition. Bar velocity was recorded with a linear position transducer and power output was calculated using velocity and load data. A two-way repeated measures ANOVA indicated no significant substance x set interaction for mean power output (MP), mean bar velocity (MV), peak power output (PP) and peak bar velocity (PV). However, there was a significant main effect of substance on MP (p < 0.01; η2 = 0.47) and MV (p < 0.01; η2 =0.45). Post hoc analysis for main effect revealed that MP and MV values in the CAF-6 group were higher than in the PLAC group in all 5 sets of the exercise (p < 0.05). In conclusion, this study demonstrated that an acute dose of caffeine before resistance exercise increased mean power output and mean bar velocity during a multiple-set bench press exercise protocol among mild caffeine users.

Eccentric Force-Velocity Characteristics during a Novel Squat Protocol in Trained Rugby Union Athletes-Pilot Study.

Eccentric strength characteristics have been shown to be important factors in physical performance. Many eccentric tests have been performed in isolation or with supramaximal loading. The purpose of this study was to investigate within- and between- session reliability of an incremental eccentric back squat protocol. Force plates and a linear position transducer captured force-time-displacement data across six loading conditions, separated by at least seven days. The reliability of eccentric specific measurements was assessed using coefficient of variation (CV), change in mean, and intraclass correlation coefficient (ICC). Eccentric peak force demonstrated good ICC (≥0.82) and TE (≤7.3%) for each load. Variables based on mean data were generally less reliable (e.g., mean rate of force development, mean force, mean velocity). This novel protocol meets acceptable levels of reliability for different eccentric-specific measurements although the extent to which these variables affect dynamic performance requires further research.

Relationships Between Sprinting, Broad Jump, and Vertical Jump Kinetics Are Limited in Elite, Collegiate Football Athletes.

Boone, JB, VanDusseldorp, TA, Feito, Y, and Mangine, GT. Relationships between sprinting, broad jump, and vertical jump kinetics are limited in elite, collegiate football athletes. J Strength Cond Res 35(5): 1306-1316, 2021-To evaluate the relationships and agreement in kinetics measured during a 10-yd sprint, a standing broad jump (SBJ), and a vertical jump (VJ), 73 collegiate football players (22.3 ± 0.8 years, 188 ± 7 cm, 113 ± 23 kg) volunteered for this cross-sectional study over a 3-year period. At the beginning of each athlete's off-season training phase and after a standard warm-up, each athlete completed 2-3 maximal trials of each test while tethered to a robotic, cable-resistance device (10-yd sprint and SBJ) or a linear position transducer (VJ alone). Force (N), velocity (m·s-1), and power (W) were measured during the first 2 steps, acceleration phase (units·step-1), and entire 10-yd sprint, and the entire SBJ and VJ. Spearman and partial correlations (controlling for stature) revealed small-to-moderate relationships (r = -0.30 to -0.34) between the second sprinting step and VJ force. Small negative relationships were also noted between sprinting and VJ force and power, but not when controlling for height. Agreement was determined by examining relationships between the differences in and averaged kinetics measured on each test. Trivial-to-small relationships (r < 0.29) were observed between sprinting (first step and 10-yd) and VJ velocity, and between VJ and SBJ velocity, although coefficient of variation (CV) ranged between 64 and 104%. All other relationships ranged from moderate-to-practically perfect with CVs exceeding 500%. Although some relationships exist between sprinting and jumping kinetics, their agreement is variable. These data suggest that coaches and athletes should not use one of these assessments in place of, or to predict performance in, the other assessments.

Use of Machine-Learning and Load-Velocity Profiling to Estimate 1-Repetition Maximums for Two Variations of the Bench-Press Exercise.

The purpose of the current study was to compare the ability of five different methods to estimate eccentric–concentric and concentric-only bench-press 1RM from load–velocity profile data. Smith machine bench-press tests were performed in an eccentric–concentric (n = 192) and a concentric-only manner (n = 176) while mean concentric velocity was registered using a linear position transducer. Load–velocity profiles were derived from incremental submaximal load (40–80% 1RM) tests. Five different methods were used to calculate 1RM using the slope, intercept, and velocity at 1RM (minimum velocity threshold—MVT) from the load–velocity profiles: calculation with individual MVT, calculation with group average MVT, multilinear regression without MVT, regularized regression without MVT, and an artificial neural network without MVT. Mean average errors for all methods ranged from 2.7 to 3.3 kg. Calculations with individual or group MVT resulted in significant overprediction of eccentric–concentric 1RM (individual MVT: difference = 0.76 kg, p = 0.020, d = 0.17; group MVT: difference = 0.72 kg, p = 0.023, d = 0.17). The multilinear and regularized regression both resulted in the lowest errors and highest correlations. The results demonstrated that bench-press 1RM can be accurately estimated from load–velocity data derived from submaximal loads and without MVT. In addition, results showed that multilinear regression can be used to estimate bench-press 1RM. Collectively, the findings and resulting equations should be helpful for strength and conditioning coaches as they would help estimating 1RM without MVT data.

Pooled Versus Individualized Load-Velocity Profiling in the Free-Weight Back Squat and Power Clean.

This study compared pooled against individualized load-velocity profiles (LVPs) in the free-weight back squat and power clean. A total of 10 competitive weightlifters completed baseline 1-repetition maximum assessments in the back squat and power clean. Three incremental LVPs were completed, separated by 48 to 72 hours. Mean and peak velocity were measured via a linear-position transducer (GymAware). Linear and nonlinear (second-order polynomial) regression models were applied to all pooled and individualized LVP data. A combination of coefficient of variation (CV), intraclass correlation coefficient, typical error of measurement, and limits of agreement assessed between-subject variability and within-subject reliability. Acceptable reliability was defined a priori as intraclass correlation coefficient > .7 and CV < 10%. Very high to practically perfect inverse relationships were evident in the back squat (r = .83-.96) and power clean (r = .83-.89) for both regression models; however, stronger correlations were observed in the individualized LVPs for both exercises (r = .85-.99). Between-subject variability was moderate to large across all relative loads in the back squat (CV = 8.2%-27.8%) but smaller in the power clean (CV = 4.6%-8.5%). The power clean met our criteria for acceptable reliability across all relative loads; however, the back squat revealed large CVs in loads ≥90% of 1-repetition maximum (13.1%-20.5%). Evidently, load-velocity characteristics are highly individualized, with acceptable levels of reliability observed in the power clean but not in the back squat (≥90% of 1-repetition maximum). If practitioners want to adopt load-velocity profiling as part of their testing and monitoring procedures, an individualized LVP should be utilized over pooled LVPs.

Acute Inflammatory, Cortisol, and Soreness Responses to Supramaximal Accentuated Eccentric Loading.

Merrigan, JJ and Jones, MT. Acute inflammatory, cortisol, and soreness responses to supramaximal accentuated eccentric loading. J Strength Cond Res 35(2S): S107-S113, 2021-The purpose was to determine differences in time under tension, cortisol, inflammation, and perceived soreness between accentuated eccentric (AEL) and traditional loading (TRA) resistance exercise protocols. Resistance-trained men (n = 21) completed the AEL and TRA protocols in a random order, separated by 48 hours (sets × reps at eccentric/concentric) as follows: AEL65, 3 × 5 at 120/65% 1 repetition maximum (RM); AEL80, 3 × 3 at 120/80% 1RM; TRA65, 3 × 5 at 65/65% 1RM; and TRA80, 3 × 3 at 80/80% 1RM. Four linear position transducers measured eccentric time under tension (ETUT) and total time under tension (TTUT). Ultrasonography measured vastus lateralis muscle thickness and echo intensity at baseline and immediately post-exercise. Salivary cortisol was assessed at baseline, 0-, 15-, 30-, and 60-minute post-exercise. Perceived soreness was assessed at baseline, 24-, and 48-hours post-exercise. During rep 1, AEL65 and AEL80 had longer ETUT and TTUT than TRA65 (p ≤ 0.002) and TRA80 (p ≤ 0.008), respectively. However, AEL65 had shorter ETUT (reps 3-5) and TTUT (reps 3-5) than TRA65 (p ≤ 0.043). Similarly, ETUT (reps 2-3) and TTUT (rep 3) was shorter in AEL80 than TRA80 (p ≤ 0.045). However, there was no protocol effect for ETUT and TTUT (p > 0.05). Muscle thickness changes were trivial after each protocol (AEL80, d = 0.19; TRA80, d = 0.15; AEL65, d = 0.24; TRA65, d = 0.23), but changes in echo intensity were moderate (AEL80, d = 0.61; TRA80, d = 0.61; AEL65, d = 0.61; TRA65, d = 0.76). Salivary cortisol decreased below baseline at 30- and 60-minute post-exercise (p ≤ 0.006). Perceived soreness elevated from baseline to 24 hours for AEL80 (p = 0.006). The inflammatory, cortisol, and soreness responses after AEL were either low or similar to TRA, indicating similar recovery patterns between protocols.

Video-Based System for Automatic Measurement of Barbell Velocity in Back Squat.

Velocity-based training is a contemporary method used by sports coaches to prescribe the optimal loading based on the velocity of movement of a load lifted. The most employed and accurate instruments to monitor velocity are linear position transducers. Alternatively, smartphone apps compute mean velocity after each execution by manual on-screen digitizing, introducing human error. In this paper, a video-based instrument delivering unattended, real-time measures of barbell velocity with a smartphone high-speed camera has been developed. A custom image-processing algorithm allows for the detection of reference points of a multipower machine to autocalibrate and automatically track barbell markers to give real-time kinematic-derived parameters. Validity and reliability were studied by comparing the simultaneous measurement of 160 repetitions of back squat lifts executed by 20 athletes with the proposed instrument and a validated linear position transducer, used as a criterion. The video system produced practically identical range, velocity, force, and power outcomes to the criterion with low and proportional systematic bias and random errors. Our results suggest that the developed video system is a valid, reliable, and trustworthy instrument for measuring velocity and derived variables accurately with practical implications for use by coaches and practitioners.

Sit-to-Stand Power Across the Lifespan: A Cross-Sectional Analysis.

Lower-body power measured by a linear position transducer during the sit-to-stand (STS) movement declines with age and may be a predictor of physical disability in older adults. The purpose of this study was to establish normative data for STS power across the lifespan and to determine if differences exist between age cohorts, sexes, and age cohort-sex subgroups. Adults (N = 557) aged 18-89 were divided into five age cohorts and performed the STS connected to a linear position transducer, which calculated power and velocity during the movement. Significantly lower (p < .01) velocity was observed in a younger age cohort in females than males, whereas males saw a significant average power decrement (p < .01) in a younger age cohort than females. STS power norms give clinicians a metric predicting physical disability and may be of particular interest to males as their power production begins to decline at an earlier age.

Validation of Velocity Measuring Devices in Velocity Based Strength Training

Abstract To control and monitor strength training with a barbell various systems are on the consumer market. They provide the user with information regarding velocity, acceleration and trajectory of the barbell. Some systems additionally calculate the 1-repetition-maximum (1RM) of exercises and use it to suggest individual intensities for future training. Three systems were tested: GymAware, PUSH Band 2.0 and Vmaxpro. The GymAware system bases on linear position transducers, PUSH Band 2.0 and Vmaxpro base on inertial measurement units. The aim of this paper was to determine the accuracy of the three systems with regard to the determination of the average velocity of each repetition of three barbell strength exercises (squat, barbell rowing, deadlift). The velocity data of the three systems were compared to a Vicon system using linear regression analyses and Bland-Altman-diagrams. In the linear regression analyses the smallest coefficient of determination (R2.) in each exercise can be observed for PUSH Band 2.0. In the Bland-Altman diagrams the mean value of the differences in the average velocities is near zero for all systems and all exercises. PUSH Band 2.0 has the largest differences between the Limits of Agreement. For GymAware and Vmaxpro these differences are comparable.

Effects of Preferred and Non-Preferred Warm-Up Music on Resistance Exercise Performance

The purpose of this study was to examine the effects of listening to preferred and non-preferred warm-up music on upper-body resistance exercise performance. Resistance-trained males (ages 18–24) participated in two separate bench press trials each with a different warm-up music condition: preferred warm-up music (PREF) or non-preferred warm-up music (NON-PREF). In each trial, participants listened to PREF or NON-PREF music during a standardized bench press warm-up. Following the warm-up, motivation to exercise was measured using a visual analog scale followed by two sets × repetitions to failure (RTF) at 75% of 1-RM separated by 1 min of rest. A linear position transducer was used to measure mean barbell velocity. Rate of perceived exertion (RPE) was obtained after each set. RTF, velocity, RPE, and motivation were analyzed. RTF were significantly higher during the PREF versus NON-PREF trail (p = 0.001) while mean barbell velocity remained unchanged (p = 0.777). RPE was not significantly different between PREF and NON-PREF trials (p = 0.735). Motivation to exercise was significantly higher during the PREF versus NON-PREF trial (p < 0.001). Findings show that listening to PREF music during a warm-up improves subsequent RTF performance during bench press exercise. However, barbell velocity was largely unaffected. While perceived exertion was similar between trials, motivation to exercise was markedly increased during the PREF warm-up music trial. These findings suggest that competitors listening to warm-up music before giving maximal effort during resistance exercise could optimize performance by ensuring self-selection of their own preferred music.

Reliability and Validity of Using the Push Band v2.0 to Measure Repetition Velocity in Free-Weight and Smith Machine Exercises.

Hughes, LJ, Peiffer, JJ, and Scott, BR. Reliability and validity of using the Push Band v2.0 to measure repetition velocity in free-weight and Smith machine exercises. J Strength Cond Res XX(X): 000-000, 2019-The purpose of this study was to investigate the test-retest reliability and concurrent validity of using the Push Band device 2.0 (PUSH) to quantify repetition velocity across 4 common resistance training exercises performed using free-weight and Smith machine training modalities. Twenty well-trained men (age: 25.1 ± 2.9 years, height: 182.4 ± 6.0 cm, body mass: 77.9 ± 12.0 kg, training age: 5.2 ± 1.4 years) visited the laboratory on 6 occasions (3 free-weight and 3 Smith machine sessions). Baseline strength assessments were conducted in the first session with each modality for squat, bench press, overhead press, and prone row exercises. The subsequent sessions featured repetitions performed with 30, 60, and 90% 1-repetition maximum. During these sessions, velocity was measured simultaneously using a validated linear position transducer (LPT; considered the criterion for this study) and 2 PUSH devices, one in body mode (PUSHBODY) and the other bar mode (PUSHBAR). Test-retest reliability was examined using the intraclass correlation coefficient (ICC) and coefficient of variation (CV). The LPT demonstrated slightly greater reliability (ICC = 0.80-0.98, CV = 0.4-5.1%) than the PUSHBODY (ICC = 0.65-0.95, CV = 0.8-6.9%) and PUSHBAR (ICC = 0.50-0.93, CV = 0.7-7.1%) devices. Near-perfect correlations existed between velocity measured using LPT and PUSH devices (r = 0.96-0.99). No significant differences existed between mean velocity measures obtained using LPT and either PUSH device. The PUSH device can be used in either bar or body mode to obtain reliable and valid repetition velocity measures across a range of loads and exercises performed using either free weights or a Smith machine.

A comparison between predetermined and self-selected approaches in resistance training: effects on power performance and psychological outcomes among elite youth athletes.

BackgroundThe aim of this study was to investigate if choice over resistance training exercise order affects motor performance and psychological outcomes among elite youth hockey players.MethodsSeventeen elite hockey players (male, n = 14; female, n = 3, age: 15.1 ± 1.1 years) participated in this study. In the first session, individual optimum power loads were calculated in the back squat, jump squat, bench press and bench throw exercises. Then, in four counterbalanced sessions, participants completed three sets of six repetitions in the same exercises loaded with their optimum power loads. In two sessions, athletes used a self-selected order of exercises, while in other two sessions the order was predetermined. Power outputs were estimated with a linear position transducer. Fatigue and enjoyment were measured during and after the sessions using standardized questionnaires. Repeated measures analyses of variance and a paired-sample t-test were used to compare the effects between conditions.ResultsWe observed trivial to small differences between conditions in power outputs (p ≥ 0.07; ES ≤ 0.21), fatigue (p ≥ 0.42; ES ≤ 0.33) and enjoyment (p = 0.72; ES = 0.05).ConclusionGiven the comparable effects between approaches, both can be used when coaching youth athletes. Self-selecting the order of exercises based on preferences is a feasible and practical coaching option when working with youth athletes.

Effectiveness of Accentuated Eccentric Loading: Contingent on Concentric Load.

To identify acute effects of a single accentuated eccentric loading (AEL) repetition on subsequent back-squat kinetics and kinematics with different concentric loads. Resistance-trained men (N = 21) participated in a counterbalanced crossover design and completed 4 protocols (sets × repetitions at eccentric/concentric) as follows: AEL65, 3 × 5 at 120%/65% 1-repetition maximum (1-RM); AEL80, 3 × 3 at 120%/80% 1-RM; TRA65, 3 × 5 at 65%/65% 1-RM; and TRA80, 3 × 3 at 80%/80% 1-RM. During AEL, weight releasers disengaged from the barbell after the eccentric phase of the first repetition and remained off for the remaining repetitions. All repetitions were performed on a force plate with linear position transducers attached to the barbell, from which eccentric and concentric peak and mean velocity, force, and power were derived. Eccentric peak velocity (-0.076 [0.124]m·s-1; P = .01), concentric peak force (187.8 [284.4]N; P = .01), eccentric mean power (-145.2 [62.0]W; P = .03), and eccentric peak power (-328.6 [93.7]W; P < .01) during AEL65 were significantly greater than TRA65. When collapsed across repetitions, AEL65 resulted in slower eccentric velocity and power during repetition 1 but faster eccentric and concentric velocity and power in subsequent repetitions (P ≤ .04). When comparing AEL80 with TRA80, concentric peak force (133.8 [56.9]N; P = .03), eccentric mean power (-83.57 [38.0]W; P = .04), and eccentric peak power (-242.84 [67.3]W; P < .01) were enhanced. Including a single supramaximal eccentric phase of 120% 1-RM increased subsequent velocity and power with concentric loads of 65% 1-RM, but not 80% 1-RM. Therefore, AEL is sensitive to the magnitude of concentric loads, which requires a large relative difference to the eccentric load, and weight releasers may not need to be reloaded to induce performance enhancement.