Agreement between the Open Barbell and Tendo Linear Position Transducers for Monitoring Barbell Velocity during Resistance Exercise

To determine the agreement between the Open Barbell (OB) and Tendo weightlifting analyzer (TWA) for measuring barbell velocity, eleven men (19.4 ± 1.0 y) performed one set of 2–3 repetitions at four sub-maximal percentage loads, [i.e., 30, 50, 70, and 90% one-repetition maximum (1RM)] in the back (BS) and front squat (FS) exercises. During each repetition, peak and mean barbell velocity were recorded by OB and TWA devices, and the average of the 2–3 repetitions was used for analyses. Although the repeated measures analysis of variance revealed significantly (p ≤ 0.005) greater peak and mean velocity scores from OB across all intensities, high intraclass correlation coefficients (ICC2,K = 0.790–0.998), low standard error of measurement (SEM2,K = 0.040–0.119 m·s−1), and coefficients of variation (CV = 2–4%) suggested consistency between devices. Positive (r = 0.491–0.949) Pearson correlations between averages and differences (between devices) in peak velocity, as well as associated Bland-Altman plots, showed greater differences occurred as the velocity increased, particularly at low-moderate intensity loads. OB consistently provides greater barbell velocity scores compared to TWA, and the differences between devices were more apparent as the peak velocity increased with low-to-moderate loads. Strength coaches and athletes may find better agreement between devices if the mean velocity scores are only considered

Effect of Multi-Ingredient Supplement Containing Satiereal, Naringin, and Vitamin D on Body Composition, Mood, and Satiety in Overweight Adults

The purpose of this investigation was to examine the effects of 28 days of a dietary supplement on body composition, mood, and satiety in overweight adults. Twenty healthy adults (25.5 ± 3.8 years; 87.3 ± 20.7 kg; 169.9 ± 10.6 cm; 29.9 ± 5.1 body mass index) participated in this randomized, double-blind, placebo-controlled investigation. Ten participants were provided with a dietary supplement containing 178 mg satiereal, 100 mg naringin, and 2,000 IU vitamin D3 daily (SUPP), and ten participants were provided a placebo (PL) for 28 days. Baseline (PRE) and post (POST) assessments included body mass, BMI, and waist circumference measures. In addition, participants provided self-reported food records and completed study questionnaires twice weekly. Questionnaires consisted of profile of mood states, visual analog scales, modified trait food-cravings questionnaire, and a modified state food-cravings questionnaire. No significant differences were noted between groups for total calorie or macronutrient intake (p = 0.65–0.92), body mass (p = 0.34), BMI (p = 0.24), or waist circumference measures (p = 0.56–0.94). In addition, no significant differences between groups were observed for mood states, subjective measures of food cravings, or feelings of anxiety, fullness, bloating, hunger, craving, and stress (p \u3e.05). In conclusion, 28 days of a dietary supplement containing satiereal, naringin, and vitamin D3 did not have any detectable beneficial effects on body-weight management

Agreement between the Open Barbell and Tendo Linear Position Transducers for Monitoring Barbell Velocity during Resistance Exercise

To determine the agreement between the Open Barbell (OB) and Tendo weightlifting analyzer (TWA) for measuring barbell velocity, eleven men (19.4 ± 1.0 y) performed one set of 2–3 repetitions at four sub-maximal percentage loads, [i.e., 30, 50, 70, and 90% one-repetition maximum (1RM)] in the back (BS) and front squat (FS) exercises. During each repetition, peak and mean barbell velocity were recorded by OB and TWA devices, and the average of the 2–3 repetitions was used for analyses. Although the repeated measures analysis of variance revealed significantly (p ≤ 0.005) greater peak and mean velocity scores from OB across all intensities, high intraclass correlation coefficients (ICC2,K = 0.790–0.998), low standard error of measurement (SEM2,K = 0.040–0.119 m·s−1), and coefficients of variation (CV = 2–4%) suggested consistency between devices. Positive (r = 0.491–0.949) Pearson correlations between averages and differences (between devices) in peak velocity, as well as associated Bland-Altman plots, showed greater differences occurred as the velocity increased, particularly at low-moderate intensity loads. OB consistently provides greater barbell velocity scores compared to TWA, and the differences between devices were more apparent as the peak velocity increased with low-to-moderate loads. Strength coaches and athletes may find better agreement between devices if the mean velocity scores are only considered

Effect of Hip Abduction Maximal Voluntary Isometric Contraction on Lumbar Motion and Power Output During the Back Squat

Background: Post-activation potentiation (PAP) is a neuromuscular phenomenon that has been shown to augment muscular force generating attributes as well as neural and sensory recruitment. While PAP has demonstrated to acutely enhance muscular performance during high-intensity activities, the effect of PAP on lumbopelvic kinematics under load remains unknown. Objectives: The purpose of this study was to examine the potential PAP effect of a hip abduction maximal voluntary isometric contraction (MVIC) on lumbar motion and power output during the barbell back squat.  Methods: Nine resistance-trained men (22.9±2.3 y; 85.0±13.8 kg; 174.3±5.1 cm) performed a set of 5 repetitions of the barbell back squat using 80% one-repetition maximum with and without a hip abduction MVIC prior to performance.  Experimental and control trials were randomized and counterbalanced among participants.  MVIC was carried out via manual long-lever hip abduction.  During the back squat exercise, lumbar motion analysis was performed using wireless motion-sensor technology, and power output was assessed via an accelerometer.  Results: No significant differences were observed between trials for lumbar flexion range of motion (ROM) (p=0.32), lumbar flexion maximum deviation (p=0.32), lumbar lateral flexion ROM (p=0.81), lumbar lateral flexion maximum deviation (p=0.98), lumbar rotation maximum deviation (p=0.70), average peak power (p=0.98), or average mean power output (p=0.99) during the squat protocol.  Conclusions: Implementation of a manual long-lever hip abduction MVIC prior to the back squat exercise did not significantly alter lumbar motion or augment power output in resistance trained males

Acute Effect of L-Citrulline Supplementation on Resistance Exercise Performance and Muscle Oxygenation in Recreationally Resistance Trained Men and Women

L-citrulline serves as a nitric oxide precursor with the potential to increase blood flow and improve resistance exercise performance, yet more research is needed to examine its ergogenic potential. To examine the effect of L-citrulline supplementation on resistance exercise performance, muscle oxygenation, and the subjective perception of effort, energy, focus, fatigue, and muscle pump, eighteen resistance-trained men (n = 11) and women (n = 7) (21.4 ± 1.8 years; 172.3 ± 7.5 cm; 76.9 ± 10.8 kg) were randomly assigned for supplementation with 8 g of L-citrulline (CIT) or a placebo (PL) in a cross-over fashion one hour prior to testing. Participants completed an isometric mid-thigh pull test (IMTP), a ballistic bench press protocol [two sets of two repetitions at 75% 1-repetition maximum (1 RM) with maximum ballistic intent], and a strength-endurance bench press protocol [five repetition-maximum sets at 75% 1RM]. Barbell velocity and power were measured via a linear position transducer during the ballistic protocol, while the repetitions completed, volume load and muscle oxygenation were quantified during the strength-endurance protocol. Subjective measures were assessed at the baseline and immediately pre- and post-exercise. Repeated measures of the analysis of variance and Bayesian equivalents revealed no significant interactions, providing evidence favoring the null hypothesis (BF10 p = 0.045, BF10 = 0.2). The results indicate that a single 8 g dose of L-citrulline did not enhance isometric force production, muscle endurance, or muscle oxygenation parameters during the protocol implemented in this study

Level of Agreement, Reliability, and Minimal Detectable Change of the MusclelabTM Laser Speed Device on Force–Velocity–Power Sprint Profiles in Division II Collegiate Athletes

This study examined the level of agreement (Pearson product-moment correlation [rP]), within- and between-day reliability (intraclass correlation coefficient [ICC]), and minimal detectable change of the MusclelabTM Laser Speed (MLS) device on sprint time and force–velocity–power profiles in Division II Collegiate athletes. Twenty-two athletes (soccer = 17, basketball = 2, volleyball = 3; 20.1 ± 1.5 y; 1.71 ± 0.11 m; 70.7 ± 12.5 kg) performed three 30-m (m) sprints on two separate occasions (seven days apart). Six time splits (5, 10, 15, 20, 25, and 30 m), horizontal force (HZT F0; N∙kg−1), peak velocity (VMAX; m∙s−1), horizontal power (HZT P0; W∙kg−1), and force–velocity slope (SFV; N·s·m−1·kg−1) were measured. Sprint data for the MLS were compared to the previously validated MySprint (MySp) app to assess for level of agreement. The MLS reported good to excellent reliability for within- and between-day trials (ICC = 0.69–0.98, ICC = 0.77–0.98, respectively). Despite a low level of agreement with HZT F0 (rP = 0.44), the MLS had moderate to excellent agreement across nine variables (rp = 0.68–0.98). Bland–Altman plots displayed significant proportional bias for VMAX (mean difference = 0.31 m∙s−1, MLS < MySp). Overall, the MLS is in agreement with the MySp app and is a reliable device for assessing sprint times, VMAX, HZT P0, and SFV. Proportional bias should be considered for VMAX when comparing the MLS to the MySp app

Effects of phosphatidic acid supplementation on muscle thickness and strength in resistance-trained men

The purpose of this study was to investigate the effects of phosphatidic acid (PA) supplementation on muscle thickness and strength following an 8-week supervised resistance-training program. Fifteen resistance trained men (22.8±3.5 y; 80.6±8.7 kg; 178.1±5.6 cm; 14.6±8.8% body fat) were randomly assigned to a group that either consumed 750 mg of PA or a placebo (PL). Testing was carried out before (PRE) and after (POST) training/supplementation for muscle thickness and strength. Muscle thickness of the rectus femoris (RF), vastus lateralis (VL), biceps brachii (BB), and triceps brachii (TB) muscles were measured via ultrasonography along with one repetition maximum (1RM) of squat, deadlift, and bench press. Analysis of covariance, using PRE values as the covariate, did not reveal any group differences for measures of muscle thickness in the RF (PA: 3.6±5.2%; PL: 3.2±4.2%, p=0.97), VL (PA: 23.4±18.1%, PL: 12.5±15.4%, p=0.37), BB (PA: 3.7±6.4%, PL: 9.6±12.4%, p=0.86), or TB (PA: 15.1±17.9%, PL: 10.7±19.3%, p=0.79). Likewise, no group differences were observed in changes in squat (PA: 8.4±4.1%, PL: 8.1±4.2%, p=0.79), deadlift (PA: 10.1±10.1%, PL: 8.9±9.5%, p=0.66), or bench press (PA: 5.7±5.5%, PL: 5.1±3.0%, p=0.76) exercises. Collectively, however, all participants experienced significant (pThe accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

The Insulin-like Growth Factor-I–mTOR Signaling Pathway Induces the Mitochondrial Pyrimidine Nucleotide Carrier to Promote Cell Growth

The insulin/insulin-like growth factor (IGF) signaling pathway to mTOR is essential for the survival and growth of normal cells and also contributes to the genesis and progression of cancer. This signaling pathway is linked with regulation of mitochondrial function, but how is incompletely understood. Here we show that IGF-I and insulin induce rapid transcription of the mitochondrial pyrimidine nucleotide carrier PNC1, which shares significant identity with the essential yeast mitochondrial carrier Rim2p. PNC1 expression is dependent on PI-3 kinase and mTOR activity and is higher in transformed fibroblasts, cancer cell lines, and primary prostate cancers than in normal tissues. Overexpression of PNC1 enhances cell size, whereas suppression of PNC1 expression causes reduced cell size and retarded cell cycle progression and proliferation. Cells with reduced PNC1 expression have reduced mitochondrial UTP levels, but while mitochondrial membrane potential and cellular ATP are not altered, cellular ROS levels are increased. Overall the data indicate that PNC1 is a target of the IGF-I/mTOR pathway that is essential for mitochondrial activity in regulating cell growth and proliferation