Quantification of horizontal force for the EXER-GENIE® resisted sprint training device.

Sport performance coaches use a range of modalities to apply a horizontal force (Fh) to athletes during resisted sprint training (RST). These modalities include parachutes, weighted vests, pulley devices, motored tethered devices, and, most notably, weighted sleds. Despite the widespread use of these devices, the resistance forces of the pulley devices have not been evaluated for reliability and accuracy. Therefore, the primary aim of this study is to quantify the Fh of a commercially available pulley device (EXER-GENIE®) and determine how resistance force is related to the load settings on the device. The secondary aim is to identify the differences in the Fh values between three EXER-GENIE® devices that use 36 m and 60 m ropes. The Fh values in the Newtons (N) of the three EXER-GENIE® devices were analyzed using a motorized winch, a lead acid battery, and an S-beam load cell. Four 10 s winch-driven trials were performed using 15 different EXER-GENIE® loads, ranging from 0.028 kg to 3.628 kg, employing two different 36 m devices and one 60 m device. The mean ± standard deviation for Fh was reported across the four trials for each load setting. All devices produced similar Fh values across lighter load settings (loads ≤0.141 kg). However, at heavier loads (loads ≥0.226 kg), the 60 m device had Fh values 50-85 N greater than those of the 36 m device. The coefficient of variation across the four trials was extremely high at light loads but sharply decreased to <10% at heavy loads. Absolute reliability was high for each device [intraclass correlation coefficient (ICC) = 0.99]. A regression analysis for Fh values and EXER-GENIE® load indicated a strong positive relationship between load and Fh values across all devices (R2 = 0.96-0.99). Caution should be exercised when using identical loads on the different-length pulley devices, as the 60 m device produced greater Fh values than the 36 m devices at load settings higher than 0.226 kg. These results can provide coaches and practitioners with a better understanding of the magnitude of resistance that is applied when prescribing EXER-GENIE® devices for higher training loads.

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 < 1) for IMTP (PL 497.5 ± 133.6 vs. CIT 492.5 ± 129.4 N), barbell velocity, and power, and repetitions completed (PL 36.7 ± 7.2 vs. CIT 36.9 ± 8.1 repetitions). There were also no significant interactions for muscle oxygenation parameters or subjective measures except perceived fatigue. Women reported greater fatigue across all time points compared to men (~1.88 au, 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.

Effect of watermelon supplementation on exercise performance, muscle oxygenation, and vessel diameter in resistance-trained men.

INTRODUCTION: Watermelon shows promise as an ergogenic aid due to its high concentration of L-citrulline, vitamins, minerals, and antioxidants. PURPOSE: The purpose of this study was to examine the effect of watermelon supplementation on exercise performance, muscle oxygenation, and vessel diameter. METHODS: In a crossover design fashion, 15 resistance-trained men (22.4 ± 2.9 years; 177.5 ± 7.1 cm; 82.7 ± 11.2 kg) were randomly assigned to supplement with either watermelon juice concentrate (WM; 2.2 g·day-1 L-citrulline) or placebo (PL) for 7 days prior to completing an experimental trial consisting of an isometric mid-thigh pull test and acute bench press protocol. Participants completed two sets of two repetitions at 75% 1 repetition maximum (1-RM) with maximum ballistic intent followed by five repetition-maximum (RM) sets at the same load. Barbell velocity and power were measured via linear position transducer during the first two sets, while volume load and muscle oxygenation were quantified during RM sets. Brachial artery diameter and subjective perception measures were assessed at baseline and immediately pre- and post-exercise. RESULTS: Except for a greater percent change in skeletal muscle oxygenation during WM compared to PL on average and across sets (mean difference = + 4.1%, p = 0.033, BF10 = 2.2-54.5), separate traditional and Bayesian analyses of variance with repeated measures, as well as paired-samples t tests for calculated summary measures, revealed no evidence favoring conditional differences in any measure of performance, perception, or muscle oxygenation. CONCLUSION: Short-term watermelon supplementation does not appear to enhance isometric force production, bench press performance, blood vessel diameter, or muscle oxygenation parameters compared to PL in resistance-trained men.

Comparison of V̇o2peak and V̇o2max at Different Sampling Intervals in Collegiate Wrestlers.

ABSTRACT: Sell, KM, Ghigiarelli, JJ, Prendergast, JM, Ciani, GJ, Martin, J, and Gonzalez, AM. Comparison of V̇o2peak and V̇o2max at different sampling intervals in collegiate wrestlers. J Strength Cond Res 35(10): 2915-2917, 2021-The purpose of this study was to determine the difference in the highest oxygen uptake (V̇o2peak) achieved during a maximal effort graded exercise test (GXT) in 20 NCAA Division I male wrestlers using breath-by-breath (BbB) values to the maximal uptake averaged across different time- and breath-based oxygen consumption sampling intervals (V̇o2max). Given the need for aerobic fitness and anaerobic power in wrestling, the accurate determination of V̇o2max is imperative if it is to be used to identify current aerobic fitness and consequently guide sport-specific training programs to address weaknesses in this area. Each subject completed a cycle ergometer GXT during which BbB data were collected via indirect calorimetry and V̇o2peak determined as the highest value. V̇o2max was considered as the average value of 3-s, 5-s, 10-s, 20-s, and 30-s sampling, and 3-b, 7-b, and 11-b sampling during the GXT. Results show that the BbB V̇o2peak was significantly higher than the 5-s, 10-s, 20-s, 30-s, and 11-b (p < 0.05). The 3-b V̇o2max was significantly higher than the 20-s and 30-s V̇o2max values (p < 0.05). The underestimation of V̇o2peak for each time-based interval sampling approach compared with BbB V̇o2peak is consistent with previous research, but the comparison of BbB data to breath-based interval sampling has not been widely addressed in prior research. The use of a 7-b sampling interval for the determination of V̇o2max may be a promising approach to minimize the systematic errors associated with BbB or less frequent sampling intervals, but future research is needed to further support its application with elite athletic populations such as those in the current study.

The Effects of Whole-Body Photobiomodulation Light-Bed Therapy on Creatine Kinase and Salivary Interleukin-6 in a Sample of Trained Males: A Randomized, Crossover Study.

Photobiomodulation therapy (PBMT) can be applied to the whole body as compared to the application of using single hand-held devices that isolate a smaller muscle area. The purpose of this study was to examine the effects of an acute dose of whole-body PBMT pre- and post-high-intensity resistance training on creatine kinase (CK) and salivary interleukin-6 (IL-6) in a sample of trained males. Twelve males (31 ± 8.3 years, 177.2 ± 5.4 cm, and 86.0 ± 7.5 kg) were part of a randomized, counterbalanced, cross-over design, whereby each participant performed a high-intensity resistance training session that consisted of the bench press, chin-up, and repeated sprints on two separate occasions. Each participant was assigned to either the PBMT or control condition on two separate weeks, with a 10-days washout period between the weeks. Creatine kinase was measured at baseline, 24, 48, and 72 h post-exercise. Salivary IL-6 was measured at baseline, 60, 90, and 120 min. A paired t-test showed no significant difference (p = 0.669) in the area under the curve (AUC) for CK during the PBMT (191.7 ± 48.3) and control conditions (200.2 ± 68.0). A Wilcoxon signed-rank test also showed no significant median difference (p = 0.155) in the AUC for salivary IL-6 during the PBMT (Mdn = 347.7) and control conditions (Mdn = 305.8). An additional Wilcoxon signed-rank test for CK percentage change from 24 to 72 h showed the PBMT condition (Mdn = -45%) to have a -18% median difference as compared to the control condition (Mdn = -41%). As such, whole-body PBMT does not significantly reduce the activity of salivary IL-6 or CK concentration during the 24 to 72-h recovery post-high-intensity resistance training.

What do Firefighting Ability Tests Tell Us About Firefighter Physical Fitness? A Systematic Review of the Current Evidence.

Fyock-Martin, MB, Erickson, EK, Hautz, AH, Sell, KM, Turnbaugh, BL, Caswell, SV, and Martin, JR. What do firefighting ability tests tell us about firefighter physical fitness? A systematic review of the current evidence. J Strength Cond Res 34(7): 2093-2103, 2020-The firefighting profession is a physiologically demanding occupation. Currently, sudden cardiac deaths account for 40-50% of firefighter job-related deaths, for which, inadequate aerobic fitness (AF) and obesity are established as risk factors. Departments have instituted firefighting physical ability tests (FPATs) as a method of quantifying readiness for occupational-related demands. A systematic review of the current literature examining the correlation between field fitness test performance and FPAT completion times was performed. The search identified 5 studies that met the eligibility criteria. The total number of subjects in the 5 studies was 265 (259 men and 6 women), including 200 professional firefighters (75.5%), 40 volunteer (15.1%), 20 officers (7.5%), and 5 recruits (1.9%). Upper-body strength (UBs) and upper-body endurance (UBe) had the strongest correlation to FPATs (r = -0.31 to -0.66; R = 0.10 to 0.44 and r = -0.27 to -0.61; R = 0.07 to 0.37; p < 0.05, respectively). Two studies suggested that AF has a weak-to-moderate relationship with FPATs (r = 0.38 and r = -0.62). Two studies showed that anaerobic capacity had weak-to-strong correlations with FPATs (r = -0.40 and r = 0.79; R = 0.16 to 0.62; p < 0.05). No studies found a statistically significant correlation between lower-body strength and FPAT performance. Further research is needed to better understand the role of field-based fitness test results on FPAT performance. An annual department-driven multicomponent fitness assessment measuring UBs, UBe, anaerobic capacity, and AF is recommended based on the evidence reviewed.

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.

Load-Velocity Relationships of the Back vs. Front Squat Exercises in Resistance-Trained Men.

Spitz, RW, Gonzalez, AM, Ghigiarelli, JJ, Sell, KM, and Mangine, GT. Load-velocity relationships of the back vs. front squat exercises in resistance-trained men. J Strength Cond Res 33(2): 301-306, 2019-The purpose of this investigation was to describe and compare changes in barbell velocity in relation to relative load increases during the back squat (BS) and front squat (FS) exercises. Eleven National Collegiate Athletic Association Division I baseball position players (19.4 ± 1.0 years; 182.4 ± 6.5 cm; and 87.2 ± 7.4 kg) performed trials at maximum speed with loads of 30, 50, 70, and 90% of their predetermined 1 repetition maximum (1RM) for both BS and FS. Peak and mean velocity was recorded during each repetition using an accelerometer. Differences between exercises and relative loading were assessed by separate 2 × 4 (condition × relative load) repeated-measures analysis of variance for mean and peak velocity. In addition, the load-velocity relationship across submaximal loadings in BS and FS were further assessed by calculating their respective slopes and comparing slopes through a paired-samples t-test. No significant condition × relative load interactions were noted for mean velocity (p = 0.072) or peak velocity (p = 0.203). Likewise, no significant differences in the slope for BS and FS were noted for mean velocity (p = 0.057) or peak velocity (p = 0.196). However, significant main effects for relative load were noted for both mean and peak velocity (p < 0.001), whereby mean and peak velocity were progressively reduced across all relative loads (i.e., 30, 50, 70, and 90% 1RM) for both the BS and FS. Our results demonstrate that the load-velocity relationships of the BS and FS exercises seem to be similar; therefore, similar approaches may be used with these squat variations when monitoring barbell velocity or implementing velocity-based strength training.

Comparison of Physical Fitness Parameters for Starters vs. Nonstarters in an NCAA Division I Men's Lacrosse Team.

Sell, KM, Prendergast, JM, Ghigiarelli, JJ, Gonzalez, AM, Biscardi, LM, Jajtner, AR, and Rothstein, AS. Comparison of physical fitness parameters for starters vs. nonstarters in an NCAA Division I men's lacrosse team. J Strength Cond Res 32(11): 3160-3168, 2018-The purpose of this study was to present a fitness profile of Division I male lacrosse players and compare the fitness attributes across different positions and starting status. Forty-one Division I men's lacrosse players (19.6 ± 1.6 years, 82.5 ± 9.5 kg, 182.0 ± 5.4 cm) volunteered to participate in the study. Fitness attributes assessed included aerobic fitness (1.5-mile run), muscular strength (1 repetition maximum bench press, squat, and hang clean), grip strength (hand dynamometer), explosive power (vertical jump), agility (3-cone drill, pro-agility), body composition (7-site skinfold), and speed (20- and 40-yard sprint). All testing was conducted by a certified strength and conditioning coach and occurred at the conclusion of pre-season training. The only significant difference across positions was for body mass, whereby defensemen were significantly heavier than attacking players (p < 0.05). Starters were significantly faster on the 3-cone drill, 20- and 40-yard sprint, and jumped significantly higher on the vertical jump compared with nonstarters (p < 0.05). Attributes pertaining to anaerobic fitness (speed, agility, and explosive power) may be better predictors of starting status than aerobic fitness in men's NCAA Division I lacrosse players. This differs from previous research on men's club lacrosse players where a difference in aerobic fitness and body composition was shown between starters and nonstarters. The normative data presented in this study may assist strength and conditioning coaches in the development of sport-specific training programs and motivate athletes toward achieving sport-specific fitness goals by helping identify areas of weakness before the start of the season.

Effects of a 6-Week Bench Press Program Using the Freak Bar in a Sample of Collegiate Club Powerlifters.

Ghigiarelli, JJ, Pelton, LM, Gonzalez, AM, Fulop, AM, Gee, JY, and Sell, KM. Effects of a 6-week bench press program using the freak bar in a sample of collegiate club powerlifters. J Strength Cond Res 32(4): 938-949, 2018-Powerlifters train using specialty bars for unstable load (UL) training. For the bench press, the acute effects of UL are mixed, with few studies that examine training interventions. The purpose of this study was to examine the effects of a 6-week bench press training program that uses the Freak Bar (FB) as compared to a traditional barbell (TB) on maximum bench press, peak force, and peak impulse. Seven men and 3 women (21 ± 2.0 years, 172.2 ± 2.9 cm, and 95.3 ± 20.3 kg) were required to bench press 2 days per week as part of a structured program. On the second bench press day, the FB and TB groups performed 3-position pause bench presses at 60-70% one repetition maximum (1RM). One repetition maximum, peak force, and peak impulse were measured before test and after test after the 6-week program. Peak force and peak impulse were tested at 3 bench positions, including the presticking, sticking, and poststicking points, defined by the distance of the barbell from the chest. Posttraining 1RM for the FB group and TB group increased 6.7% (6.78 ± 1.6 kg, p = 0.006) and 4.3% (4.5 ± 2.7 kg, p = 0.23), respectively, with no significant differences between the groups (p = 0.589, ηp = 0.044). There were no significant differences between the groups at each bench position for peak force (p = 0.606) or peak impulse (p = 0.542). Freak Bar can be an alternative for improving maximum strength and peak force but is not significantly better than TB training when performing the 3-position pause bench press.

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 >.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.

Acute Effect of Citrulline Malate Supplementation on Upper-Body Resistance Exercise Performance in Recreationally Resistance-Trained Men.

Gonzalez, AM, Spitz, RW, Ghigiarelli, JJ, Sell, KM, and Mangine, GT. Acute effect of citrulline malate supplementation on upper-body resistance exercise performance in recreationally resistance-trained men. J Strength Cond Res 32(11): 3088-3094, 2018-To investigate the effect of citrulline malate (CM) supplementation on upper-body resistance exercise performance, 12 recreationally resistance-trained men (21.4 ± 1.6 years; 163.0 ± 46.2 cm; 85.0 ± 12.4 kg) underwent 2 testing sessions administered in a randomized, double-blind fashion. During each visit, participants were provided either 8 g of CM or a placebo (PL) 40 minutes before beginning a standardized warm-up and initiating a barbell bench press resistance exercise protocol consisting of 5 sets of 15 repetitions at 75% 1 repetition maximum with 2-minute rest intervals. Participants were instructed to complete as many repetitions as possible until either reaching 15 repetitions or muscular failure. Total number of repetitions performed and power output were recorded for each set. Subjective measures of energy, focus, fatigue, and perceived exertion, along with muscle thickness of the triceps brachii, were assessed before and after exercise. Significant (p ≤ 0.05) main effects for time were observed for all variables except for subjective feelings of energy (p = 0.085). A group × time interaction (F = 2.86, p = 0.034, n = 0.21) was observed for repetitions performed, where participants performed more (p = 0.015) repetitions on set 3 during PL (5.7 ± 1.2 repetitions) compared with CM (4.6 ± 1.2 repetitions). However, during set 4, participants tended (p = 0.089) to perform more repetitions during CM (4.8 ± 1.8 repetitions) compared with PL (4.3 ± 1.3 repetitions). No other differences were observed between trials. Supplementation with 8 g of CM 40 minutes before the barbell bench press resistance exercise protocol did not increase exercise performance, augment the muscle swelling response to training, or alter subjective measures of focus, energy, and fatigue in recreationally resistance-trained men.

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 years; 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 1 repetition maximum (1RM) of squat, deadlift, and bench press. Analysis of covariance (ANCOVA), 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 (p < 0.05) improvements in each measure of muscle thickness and strength. Results of this study suggest that PA supplementation, in combination with a 3 days·week-1 resistance-training program for 8 weeks, did not have a differential effect compared with PL on changes in muscle thickness or 1RM strength.

Muscle activation during resistance exercise at 70% and 90% 1-repetition maximum in resistance-trained men.

INTRODUCTION: Muscle activation was investigated during resistance exercise with 2 relatively high-intensity loads. METHODS: Ten resistance-trained men performed the leg press exercise to repetition failure: a set at 70% of 1-repetition maximum (1RM) and a set at 90% of 1RM. Surface electromyography (EMG) was used to assess peak and mean muscle activation of the vastus lateralis, rectus femoris, and vastus medialis. RESULTS: Peak and mean EMG remained greater at 90% than 70% 1RM across all repetitions (P = 0.03 and P = 0.02, respectively). Main effects for trial were also significant for mean EMG activity of the final common repetitions (P = 0.03) favoring 90% 1RM; however, peak EMG activity was similar during the final common repetitions of the 70% and 90% 1RM sets. CONCLUSIONS: Across all repetitions, 90% 1RM appears to produce greater muscle activation during the leg press exercise, but similar peak EMG was observed during the final common repetitions of each set. Muscle Nerve 56: 505-509, 2017.

Heart Rate and Energy Expenditure in Division I Field Hockey Players During Competitive Play.

Sell, KM and Ledesma, AB. Heart rate and energy expenditure in Division I field hockey players during competitive play. J Strength Cond Res 30(8): 2122-2128, 2016-The purpose of this study was to quantify energy expenditure and heart rate data for Division I female field hockey players during competitive play. Ten female Division I collegiate field hockey athletes (19.8 ± 1.6 years; 166.4 ± 6.1 cm; 58.2 ± 5.3 kg) completed the Yo-Yo intermittent endurance test to determine maximal heart rate. One week later, all subjects wore a heart rate monitor during a series of 3 matches in an off-season competition. Average heart rate (AvHR), average percentage of maximal heart rate (AvHR%), peak exercise heart rate (PExHR), and percentage of maximal heart rate (PExHR%), time spent in each of the predetermined heart rate zones, and caloric expenditure per minute of exercise (kcalM) were determined for all players. Differences between positions (backs, midfielders, and forwards) were assessed. No significant differences in AvHR, AvHR%, PExHR, PExHR%, and %TM were observed between playing positions. The AvHR% and PExHR% for each position fell into zones 4 (77-93% HRmax) and 5 (>93% HRmax), respectively, and significantly more time was spent in zone 4 compared with zones 1, 2, 3, and 5 across all players (p ≤ 0.05). The kcalM reflected very heavy intensity exercise. The results of this study will contribute toward understanding the sport-specific physiological demands of women's field hockey and has specific implications for the duration and schedule of training regimens.

Effects of strongman training on salivary testosterone levels in a sample of trained men.

Strongman exercises consist of multi-joint movements that incorporate large muscle mass groups and impose a substantial amount of neuromuscular stress. The purpose of this study was to examine salivary testosterone responses from 2 novel strongman training (ST) protocols in comparison with an established hypertrophic (H) protocol reported to acutely elevate testosterone levels. Sixteen men (24 ± 4.4 years, 181.2 ± 6.8 cm, and 95.3 ± 20.3 kg) volunteered to participate in this study. Subjects completed 3 protocols designed to ensure equal total volume (sets and repetitions), rest period, and intensity between the groups. Exercise sets were performed to failure. Exercise selection and intensity (3 sets × 10 repetitions at 75% 1 repetition maximum) were chosen as they reflected commonly prescribed resistance exercise protocols recognized to elicit a large acute hormonal response. In each of the protocols, subjects were required to perform 3 sets to muscle failure of 5 different exercises (tire flip, chain drag, farmers walk, keg carry, and atlas stone lift) with a 2-minute rest interval between sets and a 3-minute rest interval between exercises. Saliva samples were collected pre-exercise (PRE), immediate postexercise (PST), and 30 minutes postexercise (30PST). Delta scores indicated a significant difference between PRE and PST testosterone level within each group (p ≤ 0.05), with no significant difference between the groups. Testosterone levels spiked 136% (225.23 ± 148.01 pg·ml(-1)) for the H group, 74% (132.04 ± 98.09 pg·ml(-1)) for the ST group, and 54% (122.10 ± 140.67 pg·ml) for the mixed strongman/hypertrophy (XST) group. A significant difference for testosterone level occurred over time (PST to 30PST) for the H group p ≤ 0.05. In conclusion, ST elicits an acute endocrine response similar to a recognized H protocol when equated for duration and exercise intensity.