Fat-Free Mass Index in a Large Sample of National Collegiate Athletic Association Men and Women Athletes From a Variety of Sports.

ABSTRACT: Magee, MK, Fields, JB, Jagim, AR, and Jones, MT. Fat-free mass index in a large sample of National Collegiate Athletic Association men and women athletes from a variety of sports. J Strength Cond Res 38(2): 311-317, 2024-Fat-free mass index (FFMI) can be used to categorize fat-free mass (FFM) relative to height. Normative values have been established in a variety of sports, as has suggested lower and upper thresholds of FFMI. However, FFMI has not been reported in a large sample of athletes, representing both sexes and multiple sport types. The purpose of this study was to evaluate differences in FFMI and establish normative values across a large sample of collegiate sports. A total of 1,961 athletes (men: n = 596, 10 sports; women: n = 1,365, 8 sports) participated. Height and mass were measured using a stadiometer and calibrated digital scale, respectively. Fat-free mass was assessed with air displacement plethysmography and used to calculate FFMI. Kruskal-Wallis test and one-way analysis of variance evaluated differences in FFMI in women's and men's sports, respectively. When collapsed across sport type and stratified by sex, men had a higher FFMI (21.5 ± 1.9 kg·m -2 vs. 17.9 ± 1.8 kg·m -2 ; p < 0.001). Differences occurred in FFMI across sport. In women, basketball athletes had the highest FFMI (18.9 kg·m -2 ) and highest 99th percentile for FFMI, whereas rowers had the lowest (16.9 kg·m -2 ). In men, throwers had the highest FFMI (25.7 kg·m -2 ) and highest 99th percentile, whereas volleyball athletes had the lowest (19.9 kg·m -2 ). Differences in FFMI may be attributable to dietary habits and physiological demands of respective sports. These results can provide information relative to differences in FFMI values across sports. In addition, sport-specific normative values can be used as benchmarks and targets for training, nutrition, and goal setting.

Analysis of In-Season External Load and Sport Performance in Women's Collegiate Basketball.

ABSTRACT: Brown, FSA, Fields, JB, Jagim, AR, Baker, RE, and Jones, MT. Analysis of in-season external load and sport performance in women's collegiate basketball. J Strength Cond Res 38(2): 318-324, 2024-Quantifying and monitoring athlete workload throughout a competitive season is a means to manage player readiness. Therefore, the purpose of the current study was to quantify practice and game external loads and to assess the relationship between such loads and basketball-specific performance metrics across a women's collegiate basketball season. Thirteen National Collegiate Athletic Association Division I women basketball athletes (age 20.08 ± 1.55 years) wore Global Positioning Systems sensors equipped with triaxial accelerometers for 29 games and 66 practices during the 2019-20 season. A multivariate analysis of variance was used to assess differences in external load between high- and low-minute players and across quarters within games ( p < 0.05). Bivariate Pearson correlation coefficients were run to determine relationships between external loads and metrics of basketball performance. Findings indicated that high- and low-minute athletes experienced different loads during games and practices ( p < 0.001). External loads differed by quarter, such that player load (PL) was highest in Q4 ( p = 0.007), PL·min -1 was highest in Q1 and lowest in Q4 ( p < 0.001), and explosive ratio (i.e., ratio of PL and explosive efforts) was lowest in Q3 ( p = 0.45). Relationships existed between PL·min -1 and field goals ( r = 0.41; p = 0.02) and between the explosive ratio and free throws ( r = 0.377 p = 0.04). These results can be used to inform design of training sessions with the intent to prepare athletes for the demands of the competitive season. It is recommended that future research continue to explore the relationship of sport-specific performance metrics and athlete external load.

Physiological and biomechanical responses to exercise on two different types of rowing ergometers in NCAA Division I oarswomen.

BACKGROUND: Stationary (SE) and dynamic (DE) rowing ergometers, that are utilized for indoor training and physical assessment of competitive rowers, may elicit different physiological and biomechanical responses. The present study used SE and DE ergometers to examine submaximal and peak physiological and biomechanical responses during an incremental rowing test. METHODS: Twelve National Collegiate Athletic Association (NCAA) Division I oarswomen performed seven-stage rowing tests with the last stage performed with maximal effort. Heart rate (HR), lactate (LA), oxygen uptake (VO2), ventilation (VE), stroke rate (SR), gross efficiency (GE), and rating of perceived exertion (RPE) were obtained; while trunk, hip, knee, shoulder, and elbow ranges of motion (ROM) were measured. RESULTS: SR was higher at maximal stage DE (29.3 vs. 34.8 strokes/min, p = 0.018, d = 1.213). No difference occurred in responses of maximal stage HR, RPE, VO2, VE, LA, or GE between the two ergometers. Submaximal LA and SR were greater on the DE for all submaximal stages. Submaximal VE was greater on the DE for all submaximal stages except Stage 3 (p = 0.160, d = 0.655). VO2 was higher on the DE Stages 2-5. GE was higher on the SE for Stages 2-5. Athletes showed increased trunk (p = 0.025, [Formula: see text] = 0.488) and knee (p = 0.004, [Formula: see text] = 0.668) ROM on SE. CONCLUSION: Rowing on the DE appears to elicit a greater stroke rate and more optimal joint angles especially at high intensities. Hence, the DE is worthy of consideration as a preferred ergometer for women rowers.

Differences in Cardiometabolic Biomarkers between Elementary School-Age Latinx Children with Obesity versus Healthy Weight.

OBJECTIVES: Low-income Latinx youth are disproportionately affected by obesity, which results in an increased risk of cardiometabolic abnormalities. Biomarker tracking may be useful for the early identification of obesity comorbidities in young Latinx children. Hence, we aimed to compare cardiometabolic biomarkers between age- and sex-matched pairs of elementary school-aged Latinx children with obesity versus healthy weight. METHODS: This case-control study compared cardiometabolic biomarkers between 13 pairs of age- and sex-matched elementary school-age (median 6.5 years) Latinx children with obesity (body mass index for age ≥ 95th percentile) as compared with their healthy weight (between the 5th and 85th percentiles) counterparts. Anthropometric measures and a fasted venous blood sample were taken for the analysis of lipids, glycemic, inflammatory, endocrine, and hepatic markers. Group differences were tested by the Mann-Whitney U or χ2 test. RESULTS: Cases had higher insulin (P = 0.003), hemoglobin A1c (P = 0.002), triglycerides (P = 0.023), and C-reactive protein (P < 0.001) and lower high-density lipoprotein (P = 0.002). Hepatic markers were similar, with alanine aminotransferase elevated among both groups. CONCLUSIONS: The aforementioned biomarkers may be more sensitive to higher adiposity risk in this young Latinx population; however, elevated hepatic markers may indicate an ethnic/genetic predisposition to abnormal liver function. Research should be replicated in a larger group to confirm these findings.

Athlete External Loads Across a Collegiate Men's Lacrosse Season.

ABSTRACT: Fields, JB, Jones, MT, Feit, MK, and Jagim, AR. Athlete external loads across a collegiate men's lacrosse season. J Strength Cond Res 37(8): e455-e461, 2023-Tracking and quantifying athlete workload may provide insight into best practice periodization strategies and workload management. Limited information exists detailing the external demands associated with collegiate men's lacrosse. Therefore, the purpose of this study was to investigate and compare practice, game, and positional differences across a lacrosse season. Male collegiate lacrosse athletes ( n = 17; body mass: 79.9 kg ± 9.7 kg; body fat %: 14.7 ± 3.8%) wore a global positional system device during practices ( n = 66) and games ( n = 19). External load metrics were total distance (TD), sprint distance (SD), accelerations (>3 m·s -2 ), sprint efforts, player load (PL), PL/min, and top speed. Multiple analysis of variances assessed differences in external loads across session (practice versus game) and sport position (attackers, midfielders, and defenders). A 3 × 4 analysis of variance was used to determine a position-by-time (first quarter [Q1], second quarter [Q2], third quarter [Q3], and fourth quarter [Q4]) interaction ( p < 0.05). Total distance ( p < 0.001, η2 : 0.047), SD ( p < 0.001, η2 : 0.093), sprint efforts ( p < 0.001, η2 : 0.077), PL ( p < 0.001, η2 : 0.022), and top speeds ( p < 0.001, η2 : 0.086) were all higher in games compared with practices. Attackers and defenders covered more TD ( p < 0.001, η2 = 0.0257), accelerations ( p < 0.001, η2 = 0.126), PL ( p < 0.001, η2 = 0.233), and PL/min ( p < 0.001, η2 = 0.193) than midfielders. Attackers and midfielders covered more SD ( p = 0.002 η2 = 0.043), sprint efforts ( p < 0.001, η2 = 0.053), and achieved higher top speed ( p < 0.001, η2 = 0.0063) than defenders. Volume and intensity metrics declined by Q4 in attackers and defenders ( p < 0.05), whereas external load measures did not differ across quarters for midfielders. Monitoring in-game external loads can assist coaches with individualizing training programs and preparing athletes for game demands.

Revisiting the Assessment of Strength, Power, and Change of Direction in Collegiate American Football Athletes.

ABSTRACT: Burke, AA, Guthrie, BM, Magee, M, Miller, AD, and Jones, MT. Revisiting the assessment of strength, power, and change of direction in collegiate american football athletes. J Strength Cond Res 37(8): 1623-1627, 2023-The primary purpose was to assess the effect of strength on vertical jump (VJ) and change of direction (COD) with a secondary purpose to examine if these relationships were moderated by the sport position group through path analysis using structural equation modeling. Subjects were collegiate American football athletes grouped by skill (SK; n = 98) and nonskill (NS; n = 83) sport position groups. Maximal strength was assessed by 1 repetition maximum back squat and hang clean (HC). Vertical jump was used to evaluate power. Change of direction was assessed through the 20-yard shuttle (i.e., 5-10-5) test. Multigroup path analysis examined causal pathways among variables and moderating effects of sport position. The final model revealed that VJ fully mediated the relationship between HC and COD (HC-VJ: ß = 0.408, p < 0.001; VJ-COD: ß = -0.376, p < 0.001; and HC-COD: ß = -0.137, p = 0.17) in SK. The NS showed only direct effects of HC on COD ( ß = -0.335, p < 0.001). These findings suggest that strength does not solely explain COD ability but also can serve to enhance underpinning qualities, such as relative force production in the VJ. Relationships between strength, power, and COD are different depending on the positional group. The results provide further insight into performance outcomes in field tests. It is recommended that sport position differences be considered when assessing and analyzing physical qualities in a team setting within the sport of American football.

Analysis of Accumulated Workloads and Performance Testing Across a Collegiate Women's Lacrosse Season.

ABSTRACT: Fields, JB, Kuhlman, NM, Jagim, AR, Dulak-Sigler, C, and Jones, MT. Analysis of accumulated workloads and performance testing across a collegiate women's lacrosse season. J Strength Cond Res 37(11): 2213-2221, 2023-Monitoring accumulated workloads, acute:chronic workload ratios (ACWR), and training monotony (TM) are practical methods for monitoring athlete physical stress. Performance testing provides useful information about the changing nature of physical abilities. Therefore, the purpose was to examine differences in accumulated workloads based on session type, explore seasonal trends in ACWR and TM, and assess changes in performance assessments in collegiate women's lacrosse athletes. Athletes, who were identified as starters ( n = 12), wore positional monitoring technology during training sessions ( n = 61) and games ( n = 17) and completed preseason and postseason assessments of speed, agility, power (jump tests), strength, aerobic capacity, and body composition. Separate 1-way analyses of variance were used to determine differences in accumulated workloads for session type and differences in performance assessments from preseason to postseason ( p < 0.05). When compared with games, practice sessions elicited greater ( p < 0.001) accumulated total distance, player load, repeated high-intensity efforts, accelerations, change of direction, explosive efforts, high-speed efforts ( p = 0.002), and high-speed distance ( p = 0.002). Throughout the season, ACWR and TM ranged from 0.16 to 1.40 AU and 0.68-1.69 AU, respectively. The 40-yd sprint ( p < 0.001) and pro-agility ( p < 0.001) improved from preseason to postseason, whereas no changes in aerobic capacity, lower-body power, or strength were observed ( p > 0.05). The monitoring of accumulated loads, ACWR and TM, and performance tests revealed novel information about the seasonal demands of collegiate women's lacrosse. Women lacrosse players are able to improve speed and agility throughout the season, while maintaining strength, power, and endurance, with minimal reductions in fat-free mass.

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.

Relationships between external loads, sRPE-load, and self-reported soreness across a men's collegiate soccer season.

The purpose was to examine relationships between external loads (ELs), perceived exertion, and soreness. Collegiate men soccer players (n = 19) were monitored for 72 sessions (training: n = 53; matches: n = 19). Likert scale assessments (0-6) of lower body soreness were collected prior to each session, and ELs were collected using positional monitoring technology. Session rate of perceived exertion (sRPE-load) was calculated by multiplying perceived exertion values (Borg CR-10 Scale) by respective session duration to determine internal load. Multiple analyses of variance were used to determine differences in ELs across seasons (pre-season, in-season, post-season) and sessions (training, match). Bivariate Pearson correlation coefficients and linear regression analyses were used to evaluate relationships among soreness, ELs, and sRPE-load. Greatest ELs were observed during pre-season and post-season phases (p < 0.001). Sessions with high perceived exertion and low soreness were associated with higher ELs (p < 0.05). Duration (t = 16.13), total distance (t = 9.17), sprint distance (t = 7.54), player load (t = 4.22), top speed (t = 4.69), and acceleration (t = 2.02) positively predicted sRPE-load (F = 412.9, p < 0.001, R2 = 0.75). Soreness was weakly and trivially correlated with ELs (p < 0.05). The very strong relationship between ELs and sRPE-load highlights the utility of sRPE-load as a practical means to estimate workload; however, more research into the relationship between soreness and workload is warranted.

Kinetic and Kinematic Analysis of Various Drop Jump Performances in Army Reserve Officer Training Corps Cadets.

ABSTRACT: Merrigan, JJ, O'Toole, KB, Wutzke, CJ, and Jones, MT. Kinetic and kinematic analysis of various drop jump performances in army reserve officer training corps cadets. J Strength Cond Res 36(3): 738-746, 2022-The purpose was to examine effects of sex, drop height, and external loads on drop jump mechanics in Reserve Officer Training Corps cadets and whether findings were associated with strength. Males (n = 14) and females (n = 12) completed maximal isokinetic concentric (slow-C and fast-C) and eccentric (slow-E and fast-E) knee extensions and flexions at 60°·s-1 and 180°·s-1. After 72 hours, 3 drop jumps were performed under 3 conditions (i.e., 30 cm unloaded [30UL], 30 cm loaded 15 kg [30L], and 60 cm unloaded [60UL]). No sex × condition interactions existed for any metric (p > 0.05). The 30L condition resulted in slower eccentric and concentric center of mass (COM) and angular velocities, reduced concentric vertical ground reaction forces (vGRF), and lower jump performances. Although 60UL resulted in greater eccentric COM and angular velocities, peak vGRF, impulse, and rate of force development (p < 0.008), no differences existed in jump performances. Males had faster COM and angular concentric velocities and smaller knee valgus angles, but no different vGRF compared with females. The change in the peak hip angle, because of 60UL, was associated with knee extension eccentric and concentric strength, whereas changes in knee angles were associated with eccentric strength. Likewise, eccentric strength influenced the effects of 30L on landing vGRF more so than concentric strength. Initial strength training is recommended, specifically emphasizing eccentric actions, before performing loaded (15 kg) drop jumps to reduce the increase of landing forces. However, caution may be required when performing drops from 60 cm because of increased forces, although no decline in jump performances were noted.

Comparison of Traditional and Rest-Redistribution Sets on Indirect Markers of Muscle Damage Following Eccentric Exercise.

ABSTRACT: Merrigan, JJ, Jones, MT, Malecek, J, Padecky, J, Omcirk, D, Xu, N, Peñailillo, L, and Tufano, JJ. Comparison of traditional and rest-redistribution sets on indirect markers of muscle damage following eccentric exercise. J Strength Cond Res 36(7): 1810-1818, 2022-The purpose was to investigate the effect of rest-redistribution (RR) on muscle damage after eccentric knee extensions. After 2 weeks of eccentric familiarization, 11 resistance-trained men performed 2 work-matched isokinetic unilateral eccentric knee extension protocols at 60°·s-1 using a crossover design, separated by 7 days. Subjects performed 40 repetitions with 285 seconds of rest using traditional sets (TS; 4 sets of 10 with 95 seconds of interset rest) and RR (RR; 20 sets of 2 with 15 seconds of interset rest). Muscle morphology, tensiomyography, range of motion, perceived soreness, and strength were measured before and 0, 24, 48, 72, and 96 hour after RR and TS. There were no protocol × time interactions (p < 0.05). When collapsed across protocol and compared to baseline, echo intensity of the proximal vastus lateralis was 7 ± 9% greater at 0 hour (p = 0.042), echo intensity of the distal vastus lateralis was 6 ± 7% and 9 ± 7% greater at 0 hour (p = 0.048) and 24 hour (p < 0.001), respectively, and passive ROM was 2 ± 1% lower at 48 hour (p = 0.043) after exercise. No other differences existed over time for any other variable. Thus, contrary to concentric performance where RR likely plays a large role in maintaining performance, RR during eccentric isokinetic resistance training does not strongly influence exercise performance and indications of subsequent muscle damage.

Effect of rest period configurations on systemic inflammatory response in resistance-trained women.

This investigation examined the effect of rest- redistribution (RR) on the circulating cytokine response to resistance exercise in resistance- trained women. Participants (n = 13; 24 ± 4y; 65.0 ± 10.6 kg; 160.5 ± 5.1 cm) completed two sessions of back squats at 70% of 1- repetition maximum: Traditional sets (TS: 4x10, 120-s inter- set rest) and RR (4x 2x5) with 30-s intra- set rest after 5 repetitions and 90-s inter- set rest. Serum creatine kinase (CK), IL-1ß, IL-6, IL-8, IL-10, IL-15, and IL-6/IL-10 were determined before (PRE), immediately- post (IP), and 5, 15, 30, 60 min, 24 h, and 48 h post- exercise. CK increased significantly (p < 0.05) from PRE through 24 h for TS and through 48 h for RR. IL-15 was greater for RR than TS at 48 h. A condition effect was found for IL-10 and IL-6/IL-10 with a lower IL-10 and a greater IL-6/IL-10 for RR. A time effect demonstrated that IL-1ß and IL-10 peaked at IP. IL-8 was increased from 5 min to 60 min and 24 h. IL-6/IL-10 was increased from PRE to 30 min, 60 min, and 24 h. These results suggested that rest period configuration- specific differences exist for the inflammatory response in trained women during intramuscular homoeostatic disruption.

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

ABSTRACT: 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.

Potentiating Effects of Accentuated Eccentric Loading Are Dependent Upon Relative Strength.

ABSTRACT: Merrigan, JJ, Tufano, JJ, and Jones, MT. Potentiating effects of accentuated eccentric loading are dependent upon relative strength. J Strength Cond Res 35(5): 1208-1216, 2021-The purpose was to evaluate the acute effects of accentuated eccentric loading (AEL) on bench press velocity and subsequent perceived effort (ratings of perceived exertion [RPE]) and soreness. Resistance-trained men (n = 8) and women (n = 2) completed 4 sets of 5 bench press repetitions with AEL and traditional loading (TL) using concentric loads of 50% (AEL50, TL50) and 65% (AEL65, TL65) 1-repetition maximum (1RM). Throughout each TL set, the eccentric load remained identical to the concentric. Variable resistance during the first repetition of AEL equaled 120% 1RM. Hierarchical Linear Modeling was used to evaluate differences between AEL and TL (p < 0.05). For the first repetition, AEL50 and AEL65 resulted in slower eccentric and concentric velocities. The increasing slope of eccentric and concentric velocity across repetitions was greater during AEL50 and AEL65 compared with TL50 and TL65, respectively (p < 0.05). As an individual's strength increased, AEL50 resulted in slower eccentric velocity and faster concentric velocity than TL50. The AEL65 resulted in faster concentric velocity than TL65 (p < 0.05). Mean protocol comparisons revealed trivial to small effects between AEL and TL. There were no differences in RPE or soreness between protocols with soreness ratings remaining unchanged from baseline (1.80 ± 0.20 AU; p < 0.05). Overall, AEL was not effective for increasing concentric velocity during the bench press with current loading protocols. Yet, stronger individuals may exhibit increases in concentric velocity from AEL, which may be a result of different pacing strategies employed during the eccentric phase. Furthermore, when using the current AEL protocols, eccentric intensities were increased with no greater RPE or soreness.

External and Internal Load Measures During Preseason Training in Men Collegiate Soccer Athletes.

ABSTRACT: Fields, JB, Merigan, JM, Gallo, S, White, JB, and Jones, MT. External and internal load measures during preseason training in men collegiate soccer athletes. J Strength Cond Res 35(9): 2572-2578, 2021-Collegiate athletes are exposed to high volume loads during preseason training. Monitoring training load can inform training and recovery periods. Therefore, the purpose was to examine changes in and bidirectional relationship between external and internal load metrics in men collegiate soccer athletes (n = 20; age, 20 ± 1 year). Internal load measures of heart rate variability (HRV), salivary testosterone (T) and cortisol (C), and self-assessment wellness and ratings of perceived exertion scales were collected daily. External load measures of total distance, player load, high-speed distance, high inertial movement analysis, and repeated high-intensity efforts were collected in each training session using global positioning system/global navigation satellite system technology. A 1-way analysis of variance determined weekly changes in external load, physiological, hormonal, and subjective self-assessment measures of internal load. Bidirectional prediction of external load markers and self-assessment measures on physiological and hormonal markers of internal load were assessed by hierarchical linear regression models (p < 0.05). External load measures, C, energy, sleep, and rate of perceived exertion (RPE) decreased (p < 0.01), whereas T, T:C ratio, anger, depression, and vigor increased (p < 0.01) from week 1 to week 2. Morning C positively predicted afternoon external load and post-training RPE (p < 0.05); T:C ratio negatively predicted afternoon external load and post-training RPE (p < 0.05); and morning HRV negatively predicted post-training RPE (p = 0.031). Despite reduced hormonal stress and external load across weeks, negative perceptions of fatigue increased, suggesting fatigue patterns may have a delayed response. Load may have a more belated, chronic effect on perceptions of fatigue, whereas hormonal changes may be more immediate and sensitive to change. Practitioners may wish to use a variety of external and internal load measures to understand athletes' stress responses to training.

Relationship Between External Load and Self-Reported Wellness Measures Across a Men's Collegiate Soccer Preseason.

ABSTRACT: Fields, JB, Lameira, DM, Short, JL, Merrigan, JM, Gallo, S, White, JB, and Jones, MT. Relationship between external load and self-reported wellness measures across a collegiate men's soccer preseason. J Strength Cond Res 35(5): 1182-1186, 2021-Monitoring athlete training load is important to training programming and can help balance training and recovery periods. Furthermore, psychological factors can affect athlete's performance. Therefore, the purpose was to examine the relationship between external load and self-reported wellness measures during soccer preseason. Collegiate men soccer athletes (n = 20; mean ± SD age: 20.3 ± 0.9 years; body mass: 77.9 ± 6.8 kg; body height: 178.87 ± 7.18cm; body fat: 10.0 ± 5.0%; V̇o2max: 65.39 ± 7.61ml·kg-1·min-1) participated. Likert scale self-assessments of fatigue, soreness, sleep, stress, and energy were collected daily in conjunction with the Brief Assessment of Mood (vigor, depression, anger, fatigue, and confusion). Total distance (TD), player load (PL), high-speed distance (HSD, >13 mph [5.8 m·s-1]), high inertial movement analysis (IMA, >3.5 m·s-2), and repeated high-intensity efforts (RHIEs) were collected in each training session using positional monitoring (global positioning system/global navigation satellite system [GPS/GNSS]) technology. Session rate of perceived exertion (sRPE) was determined from athlete's post-training rating (Borg CR-10 Scale) and time of training session. Multilevel models revealed the bidirectional prediction of load markers on fatigue, soreness, sleep, energy, and sRPE (p < 0.05). Morning ratings of soreness and fatigue were predicted by previous afternoon's practice measures of TD, PL, HSD, IMA, RHIE, and sRPE. Morning soreness and fatigue negatively predicted that day's afternoon practice TD, PL, HSD, IMA, RHIE, and sRPE. Morning ratings of negative mood were positively predicted by previous day's afternoon practice HSD. In addition, negative morning mood states inversely predicted HSD (p = 0.011), TD (p = 0.002), and PL (p < 0.001) for that day's afternoon practice. Using self-reported wellness measures with GPS/GNSS technology may enhance the understanding of training responses and inform program development.

Isometric Mid-thigh Pull Kinetics: Sex Differences and Response to Whole-Body Vibration.

Merrigan, JJ, Dabbs, NC, and Jones, MT. Isometric mid-thigh pull kinetics: Sex differences and response to whole-body vibration. J Strength Cond Res 34(9): 2407-2411, 2020-The purpose was to investigate whether whole-body vibration's (WBV's) effect on force-time characteristics is dependent on time and sex. Subjects (men, n = 18; women, n = 18) performed a static quarter squat with WBV (frequency: 30 Hz; amplitude: 2-4 mm) and without for 5 × 30 seconds repetitions (1:1, WBV:rest). Next, they performed 2 sets of 3 repetitions of the isometric mid-thigh pull (IMTP) with 3 minutes of intraset rest and 5 minutes of interset rest. Peak force (PF) and rate of force development (RFD) from 0 to 50, 0 to 150, and 0 to 250 milliseconds (RFD50, RFD150, and RFD250) were analyzed (p < 0.05). A significant effect of condition existed for PF (p = 0.019) and RFD from 0 to 250 seconds (p = 0.031). In women, RFD was moderately affected immediately post-WBV (p = 0.070; d = 0.49). Yet in men, the effect of WBV on RFD existed 15 minutes after exposure (p = 0.017; d = 0.36). In absolute terms men produced more PF than women (1,008.6 ± 289.7 N; p < 0.001). All RFD bands were greater in men than those of women (RFD50, 5,519.3 ± 2,927.2 N·s; RFD150, 3,361.4 ± 1,385.3 N·s; RFD250, 2,505.7 ± 867.1 N·s; p < 0.05). However, relative to fat-free mass, PF in men (40.1 ± 7.2 N·kg) was not different from women (37.7 ± 6.4 N·kg; p = 0.284). The same was true for RFD150 (21.1 ± 24.1 N·kg·s; p = 0.084) and RFD250 (10.9 ± 14.1 N·kg·s; p = 0.128). Yet, RFD50 remained greater in men (139.1 ± 33.6 N·kg·s) than that of women (86.8 ± 34.5 N·kg·s; p = 0.034). Current WBV protocols resulted in trivial to moderate effects on IMTP forces, which may be dependent on sex and time. Finally, it is recommended that women complete movements with the intent to move weight quickly to improve early RFD.

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.

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.