Athlete External Load Measures Across a Competitive Season in High School Basketball.

ABSTRACT: Askow, AT, Jennings, W, Jagim, AR, Fields, JB, Beaudoin, RG, Sanchez, GM, Weeks, JE, Oliver, JM, and Jones, MT. Athlete external load measures across a competitive season in high school basketball. J Strength Cond Res 37(11): 2206-2212, 2023-The purpose of this retrospective analysis was to quantify in-season external load and to determine if relationships existed between load metrics and basketball performance. Eleven male high school varsity basketball athletes (n = 11; mass 80.5 ± 9.6 kg, height 190.2 ± 9.4 cm, age 17.6 ± 0.7 years) were monitored across a season. PlayerLoad (PL), PL per minute (PL·min -1 ), total jumps, and explosive movements (EMs) were quantified using a commercially available local positioning unit. Basketball-specific performance metrics, including points scored, points allowed, point differentials, and shooting percentages for each quarter and game, were compiled. Data were analyzed using repeated-measure analysis of variance to evaluate differences in load by starting status, session type, game outcome, and game type. Pearson's correlation coefficients were used to assess relationships between load metrics and basketball performance. Statistical significance was set at p < 0.05. The mean values across 23 games for PL, PL·min -1 , total jumps, and EMs were 457 ± 104 AU, 10.9 ± 1.6 AU, 42.6 ± 9.6, and 46.7 ± 7.2, respectively. Relationships were observed ( p < 0.05) between PL and points scored ( r = 0.38) and free throw percentage ( r = 0.21). Further relationships were observed between PL·min -1 and free throw shooting percentage ( r = -0.27), and between points scored and total jumps ( r = 0.28), and EMs ( r = 0.26). Notable differences in game demands were observed for playing status. Meaningful differences in measures of external load were observed between each quarter of play, with the highest measures evident in quarters 1 and 3. Guards and forwards experienced minimal differences in external load during gameplay, and game outcome did not result in differences. Higher point totals corresponded with higher PL, total jumps, and EM.

Blood Biomarkers of Sports-Related Concussion in Pediatric Athletes.

OBJECTIVE: To examine changes in blood biomarkers, serum neurofilament light (Nf-L), and plasma tau, as well as the relationship between blood biomarkers and symptom reports, in athletes with a sports-related concussion. DESIGN: Prospective cohort study. SETTING: Private community-based concussion clinic. PARTICIPANTS: Athletes aged 13 to 18 years old with a diagnosed sports-related concussion presenting to a concussion clinic within 7 days of injury and noninjured athletes with no history of concussion aged 13 to 23 years old. ASSESSMENT AND MAIN OUTCOME MEASURES: Injured athletes provided a blood sample at the initial clinical evaluation and again at least 6 months after injury. Noninjured athletes provided a single blood sample. All participants completed symptom reports during each visit. Statistical comparisons of biomarker concentrations and symptom reports were conducted. RESULTS: The mean rank for tau was significantly lower for concussed athletes compared with nonconcussed athletes. In contrast, the mean rank of Nf-L was higher for concussed athletes than for nonconcussed athletes, although the difference was nonsignificant. Plasma tau was significantly lower postinjury compared with 6 months after injury, whereas serum Nf-L was significantly higher postinjury. There was a weak but significant inverse relationship observed between tau and the number of symptoms reported, but no relationship was observed between Nf-L and the number of symptoms reported. CONCLUSIONS: These data indicate that in the days following a sports-related concussion, the blood biomarkers tau and Nf-L display contrasting patterns of change but may not be related to self-reported symptom scores.

Body Composition and Bone Mineral Density of Division 1 Collegiate Track and Field Athletes, a Consortium of College Athlete Research (C-CAR) Study.

The purpose of the present study was to generate normative values for total and regional body composition in male and female Division 1 collegiate track and field athletes using dual X-ray absorptiometry. We also sought to examine body composition by event and sex. Data were used from the Consortium of College Athlete Research group. A total of 590 (male [M]/female [F] = 274/316) athletes had their height, weight, total and regional fat mass (FM), lean mass, and bone mineral density (BMD) measured. Athletes were classified into 1 of 7 categories: Jumps (M/F = 28/30); Long Distance (M/F = 104/110), Middle Distance (M/F = 27/24), Multievent (M/F = 11/9), Pole Vault (M/F = 21/27), Sprints (M/F = 54/96), and Throws (M/F = 29/20). Total and regional differences between events and sex were assessed by analysis of variance. Except for male and female throwers, all other track and field athletes' mean percent body fat (M: 10.3%-12.6%, F: 17.5%-21.6%) and visceral FM (<500 g) was low, but in a healthy range. As expected, throwers had significantly (p < 0.05) higher total and regional FM and lean mass than other events. In addition, male (1.55 ± 0.11 g/cm2) and female (1.40 ± 0.12 g/cm2) throwers had significantly greater BMD than all other events while male (1.25 ± 0.10 g/cm2) and female (1.16 ± 0.09 g/cm2) distance runners had significantly lower BMD than all other events. In conclusion, track athletes' body composition differed across events for both males and females. These measurements provide normative data on NCAA Division 1 male and female track and field athletes.

Rest Redistribution Does Not Alter Hormone Responses in Resistance-Trained Women.

Merrigan, JJ, Tufano, JJ, Fields, JB, Oliver, JM, and Jones, MT. Rest redistribution does not alter hormone responses in resistance-trained women. J Strength Cond Res 34(7): 1867-1874, 2020-The purpose was to examine acute effects of rest redistribution (RR) on perceptual, metabolic, and hormonal responses during back squats. Twelve resistance-trained women (training age 5 ± 2 years; one repetition maximum [1-RM] per body mass, 1.6 ± 0.2) performed traditional (TS, 4 sets of 10 repetitions with 120 seconds interset rest) and RR sets (4 sets of two 5 repetition clusters with 30-second intraset rest and 90-second interset rest) in counterbalanced order, separated by 72 hours. Both conditions were performed at 70% 1RM with 360 seconds of total rest. Ratings of perceived exertion (RPE) were taken after each set. Blood was sampled at baseline, after each set, and at 5, 15, 30, and 60 minutes, as well as 24 and 48 hours after training. Alpha level was p ≤ 0.05. The RPE progressively increased throughout both conditions (p = 0.002) with a greater overall mean for TS (5.81 ± 0.14) than RR (4.71 ± 0.14; p = 0.003). Lactate increased above baseline and remained elevated through 15 minutes post in both conditions (4.00 ± 0.76; p = 0.001), with greater lactate levels for TS (6.33 ± 0.47) than RR (4.71 ± 0.53; p < 0.001). Total testosterone was elevated after set 2 (0.125 ± 0.02; p = 0.011), but no other time point, while free testosterone remained unchanged. Growth hormone continually rose from baseline to set 3 and returned to baseline by 60 minutes post (20.58 ± 3.19). Cortisol and creatine kinase did not change over time. No condition × time interactions existed for any hormone (p > 0.05). Use of rest redistribution resulted in lower perceived effort and lactate responses. Yet, hormone responses during rest redistribution were no different from TS.

Positional Body Composition of Female Division I Collegiate Volleyball Players.

Bisch, KL, Bosch, TA, Carbuhn, A, Stanforth, PR, Oliver, JM, Bach, CW, and Dengel, DR. Positional body composition of female division I collegiate volleyball players. J Strength Cond Res 34(11): 3055-3061, 2020-The primary study objective was to measure positional differences in total and regional body composition among female NCAA Division I collegiate volleyball players using dual X-ray absorptiometry (DXA). The secondary objective was to examine normative age curves for fat and lean mass (LM) variables. Ninety female volleyball players from 5 universities received a DXA scan. Athletes were categorized by position: middle blocker (MB = 31), outside hitter (OH = 32), setter (ST = 9), and Libero (LB = 18). Height, body mass, total and regional fat mass (FM), LM, bone mineral density (BMD), and abdominal visceral adipose tissue were measured by DXA. Body mass distribution ratios were calculated. The secondary age analysis included a subset of 153 DXA scans (n = 83, ages 18-21 years). Front row players (i.e., MB and OH) had significantly greater total and regional LM and BMD measures (p < 0.05, all), compared with non-front row players (i.e., LB and ST). Differences in total LM (p < 0.001) were significantly influenced by height. Front row players had consistently lower mass distribution ratios compared with non-front row players (p < 0.05, all). Lean mass index (LMI, p = 0.752) and FM index (FMI, p = 0.392) were not significantly different across ages. Back row players have greater relative upper body mass, whereas mass in front row players is more evenly distributed between the upper and lower body. Bone mineral density differences may be influenced by repeated impact of jumping during the attacking and blocking actions of front row players. Minimal changes in LMI and fluctuations in FMI can be expected across an athlete's career.

Body Composition and Visceral Adipose Tissue in Female Collegiate Equestrian Athletes.

To examine measures of total and regional body composition using dual X-ray absorptiometry (DXA) in NCAA Division I collegiate equestrian athletes, 31 female collegiate equestrian athletes were matched to a population of normal controls by age and body mass index. Total and regional fat tissue mass (FM), lean tissue mass (LM), bone mineral density (BMD), and abdominal visceral adipose tissue (VAT) were measured by DXA. Equestrian athletes had a significantly (p=0.03) lower total body fat percentage (%fat) than controls. There were no significant differences in total LM and VAT between equestrian athletes and controls. However, equestrian athletes, when compared to the controls, had significantly lower leg %fat, leg FM and higher leg LM. The greater leg LM in equestrian riders resulted in a smaller upper to lower body LM ratio compared to controls. There was no difference in leg BMD between equestrian athletes and controls. There were no significant differences between the 2 styles of riding (i. e., hunt seat and western style) in regards to body composition. The lower total %fat in equestrian athletes seems to be influenced by differences in leg composition, with equestrian athletes having significantly more LM and less FM.

Total and Regional Body Composition of NCAA Division I Collegiate Baseball Athletes.

This study's purpose was to evaluate total, regional, and throwing versus non-throwing arm body composition measurements between various positions of NCAA Division I male baseball players using dual X-ray absorptiometry (DXA). Two hundred and one collegiate baseball athletes were measured using DXA. Visceral adipose tissue (VAT), total and regional fat mass (FM), lean mass (LM), and bone mineral density (BMD) were measured. Athletes were separated into: pitchers (n=92), catchers (n=25), outfielders (n=43), and infielders (n=41). ANOVA and Tukey's honest significant difference assessed total and regional differences between positions. Infielders had significantly (p<0.05) lower total LM than pitchers and outfielders. Additionally, outfielders had significantly lower total FM compared to pitchers and catchers. No significant differences between positions were observed for total BMD and VAT. Pitchers' and infielders' throwing arm demonstrated significantly greater total mass, FM, LM, and BMD compared to the non-throwing arm. Further, outfielders' throwing arm total mass, LM, and BMD were significantly higher vs. the non-throwing arm. Significant differences were observed in total and regional body composition measurements across position, in addition to differences in throwing arm vs. non-throwing arm composition. These measurement values are important to coaches and trainers as normative positional DXA data for collegiate baseball players.

Total and Regional Body Composition of NCAA Division I Collegiate Female Softball Athletes.

The purpose of this study was to evaluate total, regional, and throwing versus non-throwing arm body composition measures across the 4 major positions of NCAA Division I female softball players using dual X-ray absorptiometry (DXA) (n=128). Total and regional total mass (TM), fat mass (FM), lean mass (LM), bone mineral density (BMD), bone mineral content (BMC), and visceral adipose tissue were measured. Athletes were separated into: pitchers (n=32), catchers (n=13), outfielders (n=39), and infielders (n=44). ANOVA and Tukey's HSD assessed total and regional differences between positions. Although no significant total or regional LM differences were observed across positions, outfielders had significantly (p=0.006-0.047) lower total-body, arm, and trunk TM and FM, leg FM, and leg BMC in comparison to pitchers. The throwing arm had significantly (p<0.0001-0.018) greater LM, BMD, and BMC than the non-throwing arm for all positions. Notably, there were minimal body composition differences among softball positions, with the primary differences being that pitchers had larger total and regional fat values than outfielders. The throwing arm of all positions had greater LM, BMD, and BMC than the non-throwing arm. These values can be used by coaches and trainers as descriptive DXA data for collegiate softball players.

Body Composition and Bone Mineral Density of Division 1 Collegiate Football Players: A Consortium of College Athlete Research Study.

Bosch, TA, Carbuhn, AF, Stanforth, PR, Oliver, JM, Keller, KA, and Dengel, DR. Body composition and bone mineral density of Division 1 collegiate football players: a consortium of college athlete research study. J Strength Cond Res 33(5): 1339-1346, 2019-The purpose of this study was to generate normative data for total and regional body composition in Division 1 collegiate football players using dual-energy x-ray absorptiometry (DXA) and examine positional differences in total and regional measurements. Data were used from the Consortium of College Athlete Research (C-CAR) group. Four hundred sixty-seven players were included in this study. Height, body mass, total and regional fat mass, lean mass, and bone mineral density were measured in each athlete in the preseason (June-August). Players were categorized by their offensive or defensive position for comparisons. Linemen tended to have the higher fat and lean mass measures (p ≤ 0.05 for all) compared with other positions. Positions that mirror each other (e.g. linemen) had similar body composition and body ratios. All positions were classified as overweight or obese based on body mass index (BMI) (>25 kg·m), yet other than offensive and defensive linemen, all positions had healthy percent body fat (13-20%) and low visceral fat mass (<500 g). The data presented here provide normative positional data for total and regional fat mass, lean mass, and bone density in Division 1 collegiate football players. Player position had a significant effect on body composition measures and is likely associated with on-field positional requirements. From a player's health perspective, although all positions had relatively high BMI values, most positions had relatively low body fat and visceral fat, which is important for the health of players during and after their playing career. The increased accuracy and reliability of DXA provides greater information, regarding positional differences in college football players compared with other methods.

Different Cluster Sets Result in Similar Metabolic, Endocrine, and Perceptual Responses in Trained Men.

Tufano, JJ, Conlon, JA, Nimphius, S, Oliver, JM, Kreutzer, A, and Haff, GG. Different cluster sets result in similar metabolic, endocrine, and perceptual responses in trained men. J Strength Cond Res 33(2): 346-354, 2019-The purpose of this study was to compare the kinematic, metabolic, endocrine, and perceptual responses of 3 back squat protocols with equal loads, number of repetitions, and total rest duration. Eight strength-trained men performed 36 back squats using 75% 1 repetition maximum and 420 seconds of total rest during basic cluster sets of 4 (CS4), rest redistribution sets of 4 (RR4), and rest redistribution sets of 1 (RR1). Rating of perceived exertion (RPE), blood lactate (La), mean velocity maintenance (MVM), and mean velocity loss (MVL) were measured during exercise. Total testosterone (TT), growth hormone (GH), cortisol (C), and sex hormone-binding globulin (SHBG) were measured before exercise and 15, 30, and 60 minutes postexercise. There were no differences between protocols for MVM. However, MVL was less during RR1 compared with RR4 (p = 0.032), and neither protocol was different than CS4. All protocols resulted in similar increases in RPE and La, which remained elevated up to 30 minutes postexercise (p ≤ 0.05). In all protocols, GH increased and returned to baseline by 60 minutes postexercise (p ≤ 0.05). At 60 minutes postexercise, TT was less than all other time points (p ≤ 0.05). There were no main effects for time for SHBG or C. The data from this study show that different types of cluster set protocols can result in proanabolic physiological responses to resistance training. In addition, coaches can redistribute rest periods without affecting perceived effort or metabolic and hormonal changes if the external load, number of repetitions, and total rest time are equalized.

Changes in Creatine Kinase and Hormones Over the Course of an American Football Season.

Stone, JD, Kreutzer, A, Mata, JD, Nystrom, MG, Jagim, AR, Jones, MT, and Oliver, JM. Changes in creatine kinase and hormones over the course of an American Football Season. J Strength Cond Res 33(9): 2481-2487, 2019-The purpose of this study was to examine changes in creatine kinase and hormones over the course of an entire season of American football. A secondary purpose was to determine differences between starters and nonstarters. Fasting blood samples were obtained from 19 National Collegiate Athletic Association Division I (n = 19; 20 ± 1 years) football athletes over the course of a season beginning before the start of summer off-season conditioning (T1), before (T2) and after preseason (T3) football camp, with remaining samples taken throughout the competitive season (T4-T8). A magnitude-based inference approach was used to define outcomes. Testosterone was higher in starters before the start of the season (T1, Effect Size [ES] = 0.8) and during preconference (T4; ES = 0.7). Postcamp (T3) testosterone was lower in all players, though greater in starters (starters, 0.0%/0.3%/99.7%; nonstarters, 0.2%/2.9%/96.9%). An increase cortisol relative to baseline (T1) was observed in starters early in season (T4, ES = 0.7; T5, ES = 0.5). Creatine kinase was elevated at all time points in all athletes, with starters having higher circulating levels throughout season. These data demonstrate that changes in hormonal markers may be experienced over a season of football and differ by playing status. Differences between starters and nonstarters may be indicative of greater damage and stress experienced by starters, which may result from a greater number of repetitions.

Effect of Acute Complex Training on Upper-Body Force and Power in Collegiate Wrestlers.

Jones, MT, Oliver, JM, Delgado, JC, Merrigan, JJ, Jagim, AR, and Robison, CE. Effect of acute complex training on upper-body force and power in collegiate wrestlers. J Strength Cond Res 33(4): 902-909, 2019-To determine if chain bench press (BP) exercise would enhance acute upper-body force and power, 13 collegiate male wrestlers (mean ± SD; 20.5 ± 1 years; 174.3 ± 4.2 cm; 76.5 ± 8.3 kg) with ≥1 year of strength training participated. Session 1 included body composition ([BodPod] 8.5 ± 2.6% body fat), 3 repetition maximum (RM) BP, and familiarization with the plyometric push-up (PPU) on a force plate. Athletes were matched for 3RM BP and randomly assigned to 1 of 2 groups: Chain BP or Plate BP. One week after session 1, athletes performed the experimental protocol that consisted of: Baseline PPU, Chain/Plate BP set 1 (6 reps @ 60%), 30 seconds rest, PPU, 3 minutes rest, Chain/Plate BP set 2 (6 reps @60%), 30 seconds rest, and PPU. Independent samples t-tests analyzed physical characteristics (p ≤ 0.05). Standardized magnitude-based inferences were used to define outcomes. Aside from age (Plate BP 21.4 ± 0.8, Chain BP 19.9 ± 0.7 years), no physical differences were observed. Performance of Chain BP and Plate BP resulted in a likely (likelihoods of benefit/trivial/harm relative to the threshold for a smallest worthwhile benefit of 89 W: 0.5/9.2/90.3) and very likely (0.1/0.8/99.1) negative effect on peak power output in the PPU after set 1. Chain BP resulted in a likely positive effect on peak force in the PPU after set 1 (smallest worthwhile benefit 13 N: 82.8/16.9/0.3) and set 2 (94.7/5.2/0.1). Chain BP did not result in higher upper-body power over traditional plate loaded resistances.

Sex Differences in Resting Metabolic Rate Among Athletes.

Jagim, AR, Camic, CL, Askow, A, Luedke, J, Erickson, J, Kerksick, CM, Jones, MT, and Oliver, JM. Sex differences in resting metabolic rate among athletes. J Strength Cond Res 33(11): 3008-3014, 2019-The purpose of this study was to compare differences in resting metabolic rate (RMR) between sexes in Division III National Collegiate Athletic Association (NCAA) collegiate athletes and to identify predictors of RMR. Sixty-eight male (M) (age: 20.1 ± 1.5 years; height: 181.8 ± 5.9 cm; body mass (BM): 93.7 ± 16.3 kg; and body fat%: 16.3 ± 8.6%) and 48 female (F) athletes (age: 19.4 ± 1.3 years; height: 166.5 ± 6.0 cm; BM: 63.4 ± 12.7 kg; and body fat%: 21.5 ± 6.3%) participated in a single day of testing, which included determination of RMR using indirect calorimetry and air displacement plethysmography to measure fat mass and fat-free mass (FFM). An independent-samples t-test was used to compare differences in body composition and RMR between sexes, and regression analysis was used to identify predictors of RMR. Men had a significantly higher absolute RMR (M: 2,481 ± 209 vs. F: 1,553 ± 193 kcals·d; p < 0.001), but when adjusted for BM (M: 25.6 ± 8.3 vs. F: 25.9 ± 2.5 kcals·kg BM per day; p = 0.82) and FFM (M: 31.1 ± 10.6 vs. F: 33.6 ± 3.8 kcals·kg FFM per day; p = 0.12), these differences became nonsignificant. Regression analysis indicated that BM in both men (ß = 0.73) and women (ß = 0.88) was the strongest predictor of RMR. The results of the current study indicate minimal differences in RMR between sexes among athletic populations when adjusted for BM and FFM. In the current group of athletes, BM seems to account for the largest variability in RMR.

Effect of ACTN3 Polymorphism on Self-reported Running Times.

Kreutzer, A, Martinez, CA, Kreutzer, M, Stone, JD, Mitchell, JB, and Oliver, JM. Effect of ACTN3 polymorphism on self-reported running times. J Strength Cond Res 33(1): 80-88, 2019-This investigation examined the effect of ACTN3 genotype on self-reported distance running personal records (PRs). Of 94 (n = 94) recreationally active men and women, 82 (f = 42, m = 40; age: 22.6 ± 4.5 years; body mass index [BMI]: 23.5 ± 3.4 kg·m) reported 1-mile running PRs, whereas 57 (f = 33, m = 24; age: 23.4 ± 5.3 years; BMI: 22.9 ± 9.3 kg·m) reported 5K running PRs. Subjects were grouped by the presence (ACTN3) or absence (ACTN3) of α-actinin-3, as well as by individual genotype (RR, RX, and XX). Among female participants, ACTN3 reported 64.5 seconds faster (p = 0.048) 1-mile PRs compared with their ACTN3 counterparts. No differences were observed when comparing 5K PRs between genotypes. Two one-sided test equivalence testing revealed that none of the effects observed when comparing ACTN3 and ACTN3 were equivalent to zero. Our study confirms a reportedly greater prevalence of XX benefits for endurance performance in females when compared with males but fails to strongly link ACTN3 genotype to endurance performance. Practitioners should continue to be cautious when using genetic information for talent identification and sport selection.

Effect of Strength on Velocity and Power During Back Squat Exercise in Resistance-Trained Men and Women.

Askow, AT, Merrigan, JJ, Neddo, JM, Oliver, JM, Stone, JD, Jagim, AR, and Jones, MT. Effect of strength on velocity and power during back squat exercise in resistance-trained men and women. J Strength Cond Res 33(1): 1-7, 2019-The purpose was to examine load-velocity and load-power relationships of back squat in resistance-trained men (n = 20, 21.3 ± 1.4 years, 183.0 ± 8.0 cm, 82.6 ± 8.0 kg, 11.5 ± 5.0% total body fat) and women (n = 18; 20.0 ± 1.0 years; 166.5 ± 6.9 cm; 63.9 ± 7.9 kg, 20.3 ± 5.0% body fat). Body composition testing was performed followed by determination of back squat 1 repetition maximum (1RM). After at least 72 hours of recovery, subjects returned to the laboratory and completed 2 repetitions at each of 7 separate loads (30, 40, 50, 60, 70, 80, and 90% 1RM) in a random order. During each repetition, peak and average velocity and power were quantified using a commercially available linear position transducer. Men produced higher absolute peak and average power and velocity at all loads. When power output was normalized for body mass, significant differences remained. However, when normalizing for strength, no significant differences were observed between sexes. Furthermore, when subjects were subdivided into strong and weak groups, those above the median 1RM produced higher peak power, but only at loads greater than 60% 1RM. It was concluded that differences between men and women may be a result of strength rather than biological sex. Furthermore, training for maximal strength may be an appropriate method to augment maximal power output in those athletes who exhibit low levels of strength.

Differences in elbow extensor muscle characteristics between resistance-trained men and women.

PURPOSE: Muscular strength is suggested to be dependent upon muscle characteristics. Yet, sex-specific relationships of muscle characteristics to strength in the resistance-trained require investigation. Therefore, the purpose was to evaluate sex differences in muscle characteristics and isometric strength in the elbow extensors, as well as their respective associations. METHODS: Resistance-trained men (n = 15, mean ± SD 22 ± 4 years, 87.5 ± 12.8 kg, 16.9 ± 2.9% body fat) and women (n = 15, mean ± SD 25 ± 5 years, 59.3 ± 7.3 kg, 22.4 ± 4.2% body fat) were tested. B-mode ultrasound images assessed muscle thickness, pennation angle, and echo intensity. Muscle volume and fascicle length were estimated from previously validated equations. Maximal voluntary isometric contraction measured elbow extensors isometric strength. Independent samples t-tests and Fisher's r-to-z test examined differences between sexes. RESULTS: Sex differences existed in all muscle characteristics (p < 0.05). Men's absolute strength (27.86 ± 3.55 kg) was significantly greater than women (16.15 ± 3.15 kg), but no differences were noted when controlling for muscle volume (men 0.069 ± 0.017, women 0.077 ± 0.022 kg/cm3). Sex differences did not exist in the relationships of muscle characteristics to strength with muscle size having the largest correlations. However, the relationship between echo intensity and body fat was different in men (r = - 0.311) and women (r = 0.541, p = 0.0143). CONCLUSIONS: Sex differences in isometric elbow extensor strength are eliminated when expressed relative to muscle volume. Relationships of echo intensity and body fat were different between men and women and may be indicative of greater adipose infiltration in women.

Acute Effects of the Elevation Training Mask on Strength Performance in Recreational Weight lifters.

Jagim, AR, Dominy, TA, Camic, CL, Wright, G, Doberstein, S, Jones, MT, and Oliver, JM. Acute effects of the elevation training mask on strength performance in recreational weightlifters. J Strength Cond Res 32(2): 482-489, 2018-The Elevation Training Mask 2.0 (ETM) is a novel device that purportedly simulates altitude training. The purpose of this study was to investigate the acute effects of the ETM on resistance exercise performance, metabolic stress markers, and ratings of mental fatigue. Twenty male recreational weight lifters completed 2 training sessions of back squat and bench press (6 sets of 10 repetitions at 85% of 5-repetition maximum and seventh set to failure) as well as a maximal effort sprint test (18% body mass) with the mask (ETM) and without the mask (NM). Training evaluation included baseline and postexercise blood lactate and oxygen saturation measures. Performance evaluation included peak and average velocity bar velocity, total volume load, total work, total repetitions completed, and sprint performance. Adverse side effects were reported in 12% (n = 3) of participants, which included feelings of light headedness, anxiety, and discomfort. No differences were found in repetitions or total workload in back squat (p = 0.07) or bench press (p = 0.08) between conditions. A lower peak velocity was identified during the back squat, bench press, and sprint test in the ETM condition (p = 0.04). Blood lactate values were lower after bench press and sprint during the ETM condition (p < 0.001). Significantly lower ratings of alertness and focus for task were found after squat, bench press, and sprint test in the ETM condition compared with the NM condition (p < 0.001). Wearing the ETM during bouts of resistance training did not hinder the ability to achieve desired training volumes during the resistance training session. However, wearing the ETM does seem to attenuate the ability to maintain working velocity during training bouts and negatively influence ratings of alertness and focus for task.

Accuracy of Resting Metabolic Rate Prediction Equations in Athletes.

Jagim, AR, Camic, CL, Kisiolek, J, Luedke, J, Erickson, J, Jones, MT, and Oliver, JM. Accuracy of resting metabolic rate prediction equations in athletes. J Strength Cond Res 32(7): 1875-1881, 2018-The purpose of this study was to determine the accuracy of 5 different resting metabolic rate (RMR) prediction equations in male and female athletes. Twenty-two female (19.7 ± 1.4 years; 166.2 ± 5.5 cm; 63.5 ± 7.3 kg; 49.2 ± 4.3 kg of fat-free mass (FFM); 23.4 ± 4.4 body fat (BF) percent) and 28 male (20.2 ± 1.6 years; 181.9 ± 6.1 cm; 94.5 ± 16.2 kg; 79.1 ± 7.2 kg of FFM; 15.1 ± 8.5% BF) athletes were recruited to participate in 1 day of metabolic testing. Assessments comprised RMR measurements using indirect calorimetry, and body composition analyses using air displacement plethysmography. One-way repeated-measures analysis of variance with follow-up paired t tests were selected to determine differences between indirect calorimetry and 5 RMR prediction equations. Linear regression analysis was used to assess the accuracy of each RMR prediction method. An alpha level of p ≤ 0.05 was used to determine statistical significance. All the prediction equations significantly underestimated RMR while the Cunningham equation had the smallest mean difference (-165 kcals). In men, the Harris-Benedict equation was found to be the best prediction formula with the lowest root-mean-square prediction error value of 284 kcals. In women, the Cunningham equation was found to be the best prediction equation with the lowest root-mean-squared error value of 110 kcals. Resting metabolic rate prediction equations consistently seem to underestimate RMR in male and female athletes. The Harris-Benedict equation seems to be most accurate for male athletes, whereas the Cunningham equation may be better suited for female athletes.

Physical Demands of Multimodal Training Competitions and Their Relationship to Measures of Performance.

Jagim, AR, Rader, O, Jones, MT, and Oliver, JM. Physical demands of multimodal training competitions and their relationship to measures of performance. J Strength Cond Res 31(5): 1212-1220, 2017-The purpose of this study was to identify the physical demands of multimodal training (MMT) competitions and to determine the extent of their relationship to select measures of performance. Eighteen (>1.5 years of strength training experience) men (n = 10) and women (n = 8) (mean ± SD; age: 37.8 ± 10.6 years, height: 172.8 ± 8 cm, weight: 77.4 ± 13.2 kg, 16.6 ± 6% body fat) with experience performing MMT participated in a simulated MMT competition. All participants were assessed for body composition, countermovement vertical jump, and aerobic capacity during baseline testing. All participants then participated in a simulated MMT-style competition on a separate day within 10 days of baseline testing. The simulated MMT-style competition consisted of 3 events with 90 minutes of recovery allowed in between events. During the events, changes in blood lactate (La), heart rate (HR), and estimated V[Combining Dot Above]O2 were recorded. Bivariate (Pearson) correlations were computed to determine if a relationship existed between traditional measures of performance and those of the MMT-style competition. Significance was set at p ≤ 0.05. Mean change in La ranged between 9 and 12 mmol·L during the events. Mean HR and estimated V[Combining Dot Above]O2 values ranged from 145 to 172 b·min and 24 to 35 ml·kg·min, respectively, during the events. A strong correlation was observed (r = -0.722; p < 0.001) between aerobic capacity and time to completion for event 1. There was a strong correlation between lean body mass and lower-body strength performance (r = 0.882; p < 0.001) and time to completion for event 3 (r = -0.792; p < 0.001). A strong correlation was observed between lower-body power and time to completion for event 1 (r = -0.755; p < 0.001) and event 3 (r = -0.818; p < 0.001). Based on the results of this study, MMT-style competitions appear to be physically demanding activities performed at a high intensity with a great involvement of the anaerobic energy system and that some measures of aerobic capacity and power correlate with performance. When training for MMT-style competitions, it may be beneficial to focus on improving lower-body power and/or aerobic capacity.

Effect of Direct Whole-Body Vibration on Upper-Body Muscular Power in Recreational, Resistance-Trained Men.

Jones, MT, Martin, JR, Jagim, AR, and Oliver, JM. Effect of direct whole-body vibration on upper-body muscular power in recreational, resistance-trained men. J Strength Cond Res 31(5): 1371-1377, 2017-To determine the acute effect of whole-body vibration (WBV) on upper-body power, 15 men (mean ± SD; age 21.5 ± 2.3 years; height 173.1 ± 6.5 cm; and weight 77.2 ± 13.8 kg) with ≥1-year resistance training experience and a bench press (BP): body mass ratio ≥1.25 participated in a repeated-measures crossover design. Session 1 included body composition ([Bod Pod] 15.76 ± 6.7% body fat), 3 repetition maximum BP, and familiarization with: seated medicine ball throw (SMBT), plyometric push-up (PPU) on a force plate, and vertical WBV platform. Sessions 2-5 were randomly ordered across condition and test, separated by 24 hours, and consisted of a warm-up followed by 4 × 30-second push-up holds (2 × elbows at 90° and 2 × arms extended) performed on the vibration platform with WBV (frequency: 30 Hz, amplitude: 2-4 mm, 1:1 work: relief ratio) or no WBV. Seated medicine ball throw and PPU were tested immediately, 1, 5, and 10 minutes post. Standardized magnitude-based inferences were used to define outcomes. A likely positive effect of WBV was observed for SMBT at 10 minutes post. A likely negative effect of WBV resulted at 1 minute in time-to-peak force. A possibly positive effect was observed 10 minutes post. A possibly negative effect was observed 10 minutes post for peak power, and a likely negative effect of WBV was observed on time-to-peak power immediate post. Incorporating a 10-minute rest period is recommended when implementing power exercises after upper-body static-hold exercises during WBV exposure.