Transient Ischemic Attack in a 22-Year-Old NCAA Division I Baseball Athlete: A Case Study

CONTEXT

A healthy, 22-year-old, male NCAA Division I baseball shortstop was experiencing confusion, chest pain, and tightness during an off-season intersquad scrimmage. The patient did not have any significant medical history or mechanism of head injury. After initial evaluation from the athletic trainer, the patient's cognitive status began to quickly decline. The emergency action plan was put in place rapidly and referred the patient to the local emergency clinic.

CASE PRESENTATION

Upon arrival at the emergency department, an electrocardiogram was performed to rule out myocardial infarction or stroke. The first electrocardiogram results returned negative for any cardiac pathology, but a stroke alert was called. The patient was then transported to a level II trauma center due to continual cognitive decline. The patient was diagnosed with transient ischemic attack (TIA) secondary to an undiagnosed patent foramen ovale (PFO) that would later be diagnosed with further evaluation 2 months after the initial TIA incident. After multiple diagnostic and laboratory tests, the PFO went undetected until a 2D echocardiogram was performed and evaluated by a cardiologist.

MANAGEMENT AND OUTCOMES

After the confirmation of the congenital defect, surgical intervention was performed to correct the PFO using catheterization. Despite multiple preparticipation examinations, electrocardiograms, and examination of past family history, the PFO went undetected until the patient experienced symptoms of TIA. The discovery of PFO in this 22-year-old athletic individual is unusual because traditional screening techniques (electrocardiogram and preparticipation examinations) failed to detect the congenital defect.

CONCLUSIONS

Due to the emergent and timely actions of the athletic trainer, the patient has made a full recovery and is able to compete fully in athletic events. This case study amplifies the need for athletic trainers at all sporting events, updated and reviewed emergency action plans, rapid recognition of TIA in athletic individuals, and return-to-play protocol for an athletic individual after TIA.

Dual energy X-ray absorptiometry produces larger measurement error in non-Hispanic Caucasians than Hispanics

BACKGROUND

Dual energy X-ray absorptiometry (DXA) is often used as a criterion measure in body composition research and in clinical settings for the estimate of body fat percent (%Fat). The accuracy of DXA for predicting %Fat has primarily been conducted in non-Hispanic populations.

AIM

The purpose of this study was to determine the agreement of DXA-derived %Fat in Hispanic and non-Hispanic Caucasian adults.

METHODS

The sample consisted of Hispanic males (n = 96) and females (n = 102) and non-Hispanic Caucasian males (n = 145) and females (n = 161). The %Fat of a whole-body DXA scan was compared against a criterion 4-compartment (4C) model via constant error (CE = DXA - 4C model) and 95% limits of agreement. Also, a 2 × 2 factorial ANOVA, using CE as a dependent variable, was conducted to examine the main and interaction effects of sex and ethnicity.

RESULTS

When compared to the 4C model, DXA overestimated %Fat by 4.0% in Hispanics and 5.5% in non-Hispanic Caucasians (all p < 0.05). The 95% limits of agreement ranged from ±5.5% to ±5.9% for all group comparisons. The 2 × 2 factorial ANOVA indicated the CE was greater in non-Hispanic Caucasians than Hispanics (CE difference = 1.5%; p < 0.05).

CONCLUSION

Our findings revealed that DXA significantly overestimates %Fat in both populations (Hispanics and non-Hispanic Caucasians), when compared to a 4C model, regardless of sex (male or female). However, the error is more profound in non-Hispanic Caucasian adults. It is worth nothing that DXA may be useful for tracking changes in body composition that occur throughout a lifestyle intervention. Nonetheless, practitioners should be aware that the estimate of %Fat from DXA may be larger than the actual values obtained from a 4C model.

Assessment of Relationships Between External Load Metrics and Game Performance in Women's Lacrosse

The purpose of this study was to analyse the relationship between external load metrics with game performance for Division I collegiate female lacrosse. Data were collected using microtechnology during 26 games with 13 athletes (attackers n = 5, midfielders n = 8). External load variables included: total distance (TD), distance rate (DR), high-intensity (HI) distance, speed, HI sprints, accelerations, decelerations, metabolic equivalent distance (MED), and sprints. For attackers, goals, points, shots, and shots on goal (SOG) had low, positive associations with TD (r = 0.32 to 0.42) and MED (r = 0.39 to 0.45). For midfielders, goals, shots, and draw controls had low, positive relationships with TD (r = 0.34 to 0.41), DR (r = 0.33 to 0.45), and decelerations (r = 0.30 to 0.35). Points and SOG had low associations with TD (r = 0.35), DR (r = 0.33), accelerations (r = 0.31), and decelerations (r = 0.32 to 0.35). Turnovers demonstrated low, positive relationships with HI distance (r = 0.31) and HI sprints (r = 0.41). Though the correlations were low, they still revealed insights into workload metrics and offensive game statistics in the sport of lacrosse. Training for attackers should focus on agility and a training base for TD. Training for midfielders should focus on HI endurance and sprinting.

Personal, Work-, and Client-Related Burnout Within Strength and Conditioning Coaches and Personal Trainers

ABSTRACT

Snarr, RL and Beasley, VL. Personal, work-, and client-related burnout within strength and conditioning coaches and personal trainers. J Strength Cond Res 36(2): e31-e40, 2022-The purpose of this investigation was to examine the prevalence and influencing factors of personal, work-related, and client-related burnout within strength and conditioning coaches (SCCs) and personal trainers (PTs). Two hundred fifty-six SCCs (n = 141) and PTs (n = 115) completed the Copenhagen Burnout Inventory (CBI), a 19-item survey, measuring 3 subscales of personal, work-related, and client-related burnout. Information regarding other burnout-related factors (i.e., job satisfaction, social support, fitness level, and mental toughness) was solicited through single-item or multiple-item questionnaires. Correlational analyses and independent t-tests were conducted to assess associations and between-group differences between burnout and all continuous factors. Seventy-one subjects completed the survey before March 2020; after which, a worldwide pandemic (i.e., COVID-19) occurred possibly affecting employment workloads and work-related stress. Thus, post hoc analyses were conducted to assess differences in burnout scores pre-COVID-19 and post-COVID-19. Using a CBI subscale cutoff score of ≥50, fitness professionals reported 32.8% of personal burnout, 28.5% work-related burnout, and 18.0% client-related burnout. Factored by occupation, SCCs reported 32.6% personal burnout, 27.7% work-related burnout, and 18.4% client-related burnout. Within PTs, 33.0% reported personal burnout, 29.6% reported work-related burnout, and 17.4% reported client-related burnout. Higher levels of burnout, across all scales, were observed in those who were PTs, women, unmarried, living alone, would not choose to be a fitness professional again, and took the survey post-COVID as compared to their respective counterparts. Findings suggest that fitness professionals are not exempt from the stressors associated with personal and occupational burnout. Strength and conditioning coaches and PTs may reduce the risk of burnout by increasing social support, continuing education, and allowing for personal-care time with the intention of buffering these factors.

Impact of Spotter Sex on One Repetition Maximum Bench Press Performance

ABSTRACT

Nickerson, BS, Salinas, G, Garza, JM, Cho, S, and Snarr, RL. Impact of spotter sex on one repetition maximum bench press performance. J Strength Cond Res 35(9): 2397-2400, 2021-Resistance exercise is popular because of favorable health outcomes associated with increased muscular fitness. For these reasons, 1 repetition maximum (1RM), mean velocity (MV), and peak power (PP) are of interest during the bench press. However, research has yet to evaluate whether spotter sex impacts bench press performance. Therefore, the purpose of this study was to determine the impact of spotter sex on bench press performance during a 1RM testing protocol. Twenty resistance-trained individuals (10 men and 10 women) visited the laboratory on 2 separate occasions. Estimated 1RM was self-reported by subjects before the 1RM protocol. During their visits, subjects had their 1RM (kg), MV (m·s-1), and PP (W) determined on a bench press 1RM protocol while using a male or female spotter. Deception was used by telling subjects the intent of the study was to determine the reliability of a linear position transducer for measuring MV and PP during the 1RM trials. The main findings revealed that measured 1RM values for male weight lifters were significantly higher than estimated 1RM values when using both a male (p = 0.01) and female spotter (p < 0.01). In addition, results revealed MV and PP were significantly higher for the 1RM trials when male weight lifters had a male spotter (both p < 0.01). Alternatively, there were no significant differences in estimated vs. measured 1RM values for women as well as no effect of spotter sex on bench press strength (all p > 0.05). Practitioners should note that sex of a spotter does not seem to impact measured 1RM. However, notable influences may be observed within MV and PP.

Effect of Bench Press Load Knowledge on One Repetition Maximum Strength

ABSTRACT

Snarr, RL, Adams, K, and Cook, J. Effect of bench press load knowledge on one repetition maximum strength. J Strength Cond Res 35(8): 2121-2126, 2021-Knowledge of a given load and visual feedback are crucial while performing a given task. Although previous literature has examined the consequences of lifting a submaximal weight, the removal of load knowledge has yet to be examined under maximal effort. Therefore, the purpose of this investigation was to examine the differences in 1 repetition maximum (1RM) bench press values between a known and unknown external load. Twenty resistance-trained subjects (10 male subjects and 10 female subjects) completed 2 trials of a 1RM bench press protocol separated by 48-72 hours. The two 1RM trials consisted of (a) a traditional 1RM lift in which subjects could see the external load and (b) a 1RM lift in which the external load was blocked from view of the subject. Trials were randomized for all subjects. Results indicated that no differences were observed when the load was known vs. unknown within all subjects (p = 0.094; Cohen's d = 0.03; intraclass correlation coefficient = 0.99). In addition, 40% decreased and 15% increased their 1RM, despite the unknown condition. A statistical difference was found between the initial 1RM estimation vs. measured 1RM during the known load trial (p = 0.034, Cohen's d = 0.07). Practitioners should note that load knowledge before a maximal lift does not appear to present any significant detrimental effects on performance. Therefore, training during a "blinded" condition may present a unique modality and additional balance component that would not be presented during a traditional maximal lift. Further examination of attentional focus and muscle activation differences are warranted.

Acute Effect of Popular High-Intensity Functional Training Exercise on Physiologic Markers of Growth

ABSTRACT

Kliszczewicz, B, Markert, CD, Bechke, E, Williamson, C, Clemons, KN, Snarr, RL, and McKenzie, MJ. Acute effect of popular high-intensity functional training exercise on physiologic markers of growth. J Strength Cond Res 35(6): 1677-1684, 2021-Constantly evolving, high-intensity functional training (HIFT) exercise consists of various modalities, orders, weights, and repetition schemes. High-intensity functional training has gained popularity among the general population, but lacks empirical evidence regarding acute adaptive responses. The purpose of this study was to describe the acute effects of 2 representative bouts of HIFT on physiologic markers of growth. For convenience, the bouts are designated "short" (<5 minutes) and "long" (∼15 minutes), although duration was not the only difference between bouts. Ten apparently healthy men (28.1 ± 5 years) performed 2 HIFT bouts in a randomized crossover design. Blood was collected at 5 time points (Pre, Post, 1, 3, and 6 hours) to examine growth hormone (GH), insulin-like growth factor (IGF-1), insulin-like growth factor binding proteins 1 and 2 (IGFBP-1 and IGFBP-2), and vascular endothelial growth factor (VEGF). Blood lactate concentration ([La]) was analyzed at the Pre and Post time points. A repeated-measures analysis of variance (ANOVA) revealed no trial differences among the markers (IGF-1, IGFBP-1, IGFBP-2, and VEGF) except GH at Post, where the long bout produced a greater effect (p = 0.005). Mean GH levels (pg·ml-1) in the short bout increased from 68.4 to 106.5, and in the long bout, mean GH levels increased from 38.5 to 286.4. The repeated-measures ANOVA revealed a main time effect in GH (p = 0.037), while a post hoc t-test demonstrated elevated GH at 1 hour (p = 0.018) when compared with Pre. No time-dependent change (p > 0.05) was observed in IGF-1, IGFBP-1, IGFBP-2, or VEGF. Mean blood [lactate] increased more than tenfold in both bouts. The findings of this descriptive study suggest that, other than GH, there are no acute differences in markers of skeletal muscle or vascular growth between these 2 specific HIFT bouts.

Fitness Policies Within the Fire Service: A Pilot Investigation of Exercise Adherence on Fitness Outcomes Among Rural Firefighters

The purpose of this study was to investigate the adherence to departmental fitness policies and to evaluate the impact of on-duty firefighters’ adherence to fitness outcomes. This cross-sectional designed study utilized a convenience sample of 40 career firefighters from one department in rural southeast Georgia. Onsite gym attendance logs were recorded during a 10-month period. Firefighters were classified as lowest (0-16 sessions), low (17-30 sessions), moderate (31-44 sessions), or high (45+ sessions) adherence for analyses based on gym attendance. The fitness outcomes were retrieved from required annual fitness testing, including measurements of muscular strength (1RMest leg press and 1RMest bench press), muscular endurance (pushup), muscle power (vertical jump), cardiovascular fitness (submaximal treadmill), mobility (functional movement screen), and flexibility (shoulder elevation). Only 12.5% (n = 5) of firefighters complied with the department’s fitness policy of a minimum 75% adherence rate. Furthermore, there were significant differences (P ≤ .05) between various muscular strength, endurance, and flexibility between adherence rates. This study indicated that firefighters that complied more with the fitness policies were more physically fit than those that did not. Considerations should be made to promote and enforce departmental fitness policies to ensure that firefighters can physically perform their responsibilities.

V[Combining Dot Above]O2peak Comparison of a Treadmill Vs. Cycling Protocol in Elite Teenage Competitive Runners, Cyclists, and Swimmers

ABSTRACT

Marko, D, Bahenský, P, Snarr, RL, and Malátová, R. V[Combining Dot Above]O2peak Comparison of a treadmill vs. cycling protocol in elite teenage competitive runners, cyclists, and swimmers. J Strength Cond Res XX(X): 000-000, 2021-The purpose of this study was to compare the cardiorespiratory and metabolic responses of a maximal graded exercise test (GXT) on a treadmill and cycle ergometer in elite-level, youth competitive athletes. Thirty-one athletes (11 distance runners, 11 mountain-bike cyclists, and 9 long-distance swimmers) were randomly selected to complete either a running or cycling GXT on the first day, followed by the alternative 72 hours apart. The initial work rate for each GXT was set at 50% of the individuals' previously established V[Combining Dot Above]O2peak to elicit fatigue within 8-12 minutes. For the treadmill protocol, speed was increased by 1 km·h-1 each minute, with a constant 5% grade, until volitional fatigue. Cycle ergometer work rate was increased by 30 W every minute until volitional fatigue or the inability to maintain proper cadence (i.e., 100 ± 5 rev·min-1). Throughout both testing sessions, V[Combining Dot Above]O2peak, heart rate [HR] peak, breathing frequency (BF), tidal volume (VT), and minute ventilation (VE) were assessed and used to compare within-sport differences. Runners displayed a higher V[Combining Dot Above]O2peak (∼7%; d = 0.92), HRpeak (4%; d = 0.77), VE (6%; d = 0.66), and BF (12%; d = 0.62) on the treadmill vs. cycle. However, the cycling group demonstrated a greater V[Combining Dot Above]O2peak (∼8%; d = 0.92), VT (∼14%; d = 0.99), and VE (∼9%; d = 0.78) on the cycle, despite no change in HRpeak. For swimmers, the treadmill GXT elicited higher values in V[Combining Dot Above]O2peak (∼5%; d = 0.75), BF (∼11.5%; d = 0.78), and HRpeak (3%; d = 0.69). Collectively, these findings indicate that exercise mode may greatly affect physiological outcome variables and should be considered before exercise prescription and athletic monitoring.

Validity of Wearable Electromyographical Compression Shorts to Predict Lactate Threshold During Incremental Exercise in Healthy Subjects

ABSTRACT

Snarr, RL, Tolusso, DV, Hallmark, AV, and Esco, MR. Validity of wearable electromyographical compression shorts to predict lactate threshold during incremental exercise in healthy subjects. J Strength Cond Res 35(3): 702-708, 2021-Determination of lactate threshold (LT) is an important variable in improving cardiovascular endurance and performance. Unfortunately, monitoring LT during exercise uses a costly, invasive blood analysis. Recently, electromyography (EMG) has been deemed a potential method of monitoring exercise intensity and may provide a noninvasive technique to monitor lactate during exercise. The purpose of this investigation was to determine if wearable surface EMG technology, acquired from specialized compression shorts, could estimate the LT work rate during incremental cycling. Thirteen men (n = 9) and women (n = 4) completed a maximal exercise test on a cycle ergometer. Blood lactate was measured every minute, whereas EMG was recorded throughout at the site of the vastus lateralis. Lactate and EMG thresholds were calculated using the Dmax method and compared using a Wilcoxon matched-pairs signed-rank test. Results demonstrated no significant differences between lactate and EMG thresholds in regards to work output (p = 0.83), percent maximal heart rate (p = 0.13; Cohen's d = 0.43), or percent peak oxygen consumption (p = 0.64; Cohen's d = 0.09). This confirms that both lactate and EMG exhibit similar properties (i.e., increasing exponential values) during incremental exercise. A possible mechanism includes the rise in blood lactate concentration, which increases motor unit recruitment in an attempt to maintain proper cadence and force output during incremental exercise. Thus, a coincidental, exponential increase in EMG amplitude may occur. Therefore, wearable EMG compression gear may provide a viable field tool for monitoring training intensity and predicting LT work rates.

Evaluation of Load-Velocity Relationships and Repetitions-to-Failure Equations in the Presence of Male and Female Spotters

Nickerson, BS, Williams, TD, Snarr, RL, Garza, JM, and Salinas, G. Evaluation of load-velocity relationships and repetitions-to-failure equations in the presence of male and female spotters. J Strength Cond Res 34(9): 2427-2433, 2020-The purpose of this study was 2 fold: (a) to determine whether differences in mean concentric velocity (MCV), repetitions-to-failure (RTF), measured 1 repetition maximum (1RM), and 1RM prediction methods vary between lifter and spotter sex and (b) determine the accuracy of velocity-based 1RM (MCV1RM) and repetitions-to-failure-based 1RM (RTF1RM) prediction equations in the presence of either a male or female spotter. Twenty resistance-trained individuals (50% men) participated in this study. The initial 2 visits involved measuring 1RM for the bench press with a male or female spotter. Visits 3 and 4 required subjects to lift loads at 30 (5-repetitions), 50 (5-repetitions), and 70% 1RM (RTF) in the presence of a male or female spotter. Velocity-based 1RM was determined through individual regression equations using the submaximal loads (MCV30, MCV50, and MCV70). Repetitions-to-failure-based 1RM was determined through the RTF at 70% 1RM using Wathen (Wathen1RM), Mayhew (Mayhew1RM), and Epley (Epley1RM) equations. There were significant interactions when assessing Wathen1RM and Mayhew1RM (p < 0.05). Female lifters produced significantly higher estimated 1RM values during the male spotter condition using Wathen1RM and Mayhew1RM than the female spotter condition (p = 0.032 and 0.033, respectively). MCV1RM and Epley1RM produced smaller mean differences than Wathen1RM and Mayhew1RM when compared with measured 1RM. However, MCV1RM produced the largest standard error of estimate, whereas Epley1RM produced the lowest values. Epley1RM should be used over MCV1RM, Wathen1RM, and Mayhew1RM when loads up to 70% 1RM are implemented. Also, spotter sex only seems to impact female lifters when using the RTF1RM prediction equations of Wathen1RM and Mayhew1RM.

Relationship between pre-training wellness scores and internal and external training loads in a Division I women's lacrosse team

This study examined the relationship between pre-training wellness scores and internal and external training load outputs during the preparation phase of a Division I women's collegiate lacrosse team. Athletes (n = 27) logged daily wellness (sleep, energy, stress, and how their muscles felt), session ratings of perceived exertion, and training metrics for 13 weeks. Load metrics were collected with microtechnology units. Repeated measures mixed linear models were constructed to evaluate the relationships between wellness and training load. The largest effects observed indicated: improved sleep was predictive of increased total distance (by as much as 310.5 m, 95%CI 36.7-584.3), high-intensity distance (by as much as 72.7 m, 95%CI 17.2-128.3), and Athlete Load (by as much as 6.8AU, 95%CI 1.8-11.8); more energy was predictive of increased total distance (by as much as 323.6 m, 95%CI 52.2-594.9) and Athlete Load (by as much as 5.6AU. 95%CI 0.6-10.5). For each one-unit increase in overall wellness score, total distance (3.5 m, 95%CI 1.2-15.1) and Athlete Load (0.2AU, 95%CI 0.0-0.3) increased. Pre-training wellness scores and sub-scores are predictive of external load training output. Monitoring athlete wellness systematically can help coaches with decision-making relevant to training and game performance.

The Relationship Between the National Football League Scouting Combine and Game Performance Over a 5-Year Period

Cook, J, Ryan, GA, Snarr, RL, and Rossi, S. The relationship between the National Football League scouting Combine and game performance over a 5-year period. J Strength Cond Res 34(8): 2492-2499, 2020-There has been doubt on the ability of the National Football League (NFL) Scouting Combine to predict successful future game performance. This study analyzed data from athletes who participated in the Combine between 2013 and 2017 (n = 1,537) and their subsequent year's performance in the NFL. Data from 6 athletic measures were normalized for each athlete when compared with all other athletes (avgCZ) and athletes of the same position (avgPZ). Correlational analysis was used to ascertain whether the physical performance tests were associated with subsequent year's game performance (avgS). A multiple linear regression was performed to examine whether individual event Combine performance could predict the subsequent year's avgS in the NFL. Of the 35 correlations found when examining relationships, only 2 correlations were found to be moderately strong, avgCZ-avgS2 (r = 0.320), avgPZ-avgS2 (r = 0.332), whereas most were found to be weak (r < 0.3). Furthermore, data analysis suggests that Combine measures can only explain approximately 2.6% of the variance in avgS 1 year after the Combine when using 3 (vertical jump, bench press, and PRO) performance tests as predictors. The primary results of this study suggest that the NFL Combine lacks predictive ability when examining first year game performance. Furthermore, it also lacks correlational strength when examining relationships between performance and subsequent 5-year performance in the NFL. Caution should be used if coaches, general managers, and other front office staff are considering the use of Combine data as a possible selection for the upcoming NFL Draft.

Seasonal Training Load Quantification and Comparison in College Male Soccer Players

Ryan, GA, Snarr, RL, Eisenman, ML, and Rossi, SJ. Seasonal training load quantification and comparison in college male soccer players. J Strength Cond Res XX(X): 000-000, 2020-Monitoring and quantification of training load (TL) throughout a competitive soccer season is important to ensure players are able to perform throughout the season. The intent of this study was to examine the positional demands and patterns of select measures of TL during a 14-week season in collegiate male soccer players. Heart rate (HR), running performance (SZ), and perceived recovery data were collected daily using a bioharness for each subject (n = 21). Data were grouped into 2- to 3-week training blocks (Pre1, Pre2, In1, In2, In3, and In4). Continuous variables were analyzed using a multivariate analysis of variance, with post hoc Least Squared Difference pairwise comparisons. Significant positional differences were observed across the season. During Pre1, center midfielders (CM) spent more time in %HRlow compared to center backs (CB) (p < 0.01), wide midfielders (p < 0.01), and center forwards (p = 0.04). Center midfielders spent greater time in SZlower than CB (p < 0.01) and wide backs (WB) (p = 0.01). Wide backs spent greater time in SZupper compared to other positions (all p < 0.01). During Pre2, WB spent more time in %HRhigh and SZupper compared to other positions (all p < 0.01). Positional differences were more varied throughout in-season comparisons, but generally, WB and CB demonstrated higher intensities in variables compared to other positions. Tracking variations in positional TLs across the season is important for coaching and training staffs to determine player readiness and plan future training sessions, while helping to mitigate overuse injuries during a long competitive season.

Individual and Combined Effect of Inter-repetition Rest and Elastic Bands on Jumping Potentiation in Resistance-Trained Men

Nickerson, BS, Williams, TD, Snarr, RL, and Park, K-S. Individual and combined effect of inter-repetition rest and elastic bands on jumping potentiation in resistance-trained men. J Strength Cond Res 33(8): 2087-2093, 2019-The purpose of this study was to determine the individual and combined effects of cluster sets (CS) and elastic bands for jumping potentiation in resistance-trained men. Twelve resistance-trained men (age: 22 ± 3 years) participated in this study. In a random order, participants completed 1 set of 3 repetitions at 85% 1-repetition maximum for the parallel back squat: (a) traditional set with continuous repetitions; (b) continuous repetitions with elastic bands (BANDS); (c) CS with 30 seconds of rest between each repetition (CS30); and (d) CS with 30 seconds of rest between each repetition and elastic bands (CS + BANDS). Vertical jump height (JH) and peak power (PP) were measured before exercise (baseline) and at 1, 4, 7, and 10 minutes after exercise for each condition. Results revealed that PP at 10 minutes was significantly higher than 7 minutes for BANDS (p = 0.035) and that 4 and 7minutes were both significantly higher than baseline for CS + BANDS (p = 0.008 and 0.031, respectively). No other differences were observed. There were medium effect sizes (ESs) for PP with BANDS (ES = 0.58 at 10 minutes), CS30 (ES = 0.53 and 0.64 at 7 and 10 minutes, respectively), and CS + BANDS (ES = 0.64, 0.78, and 0.66 at 4, 7, and 10 minutes, respectively). All remaining ES for JH and PP were trivial to small. Based on the moderate magnitude of effect, BANDS, CS30, and CS + BANDS were effective at potentiating vertical jump power. CS + BANDS is a more practical approach to potentiate vertical jump power when athletes are under strict time restraints.

Comparison of Lactate and Electromyographical Thresholds After an Exercise Bout

Snarr, RL, Esco, MR, Tolusso, DV, Hallmark, AV, Earley, RL, Higginbotham, JC, Fedewa, MV, and Bishop, P. Comparison of lactate and electromyographical thresholds after an exercise bout. J Strength Cond Res 33(12): 3322-3331, 2019-The electromyographical threshold (EMGT) has been previously validated as a means to predict the work rate at which lactate threshold (LT) occurs. The reliability of these measures has yet to be examined after a bout of exercise. The purpose was to determine the agreement between electromyography (EMG) and LT after a 30-minute bout of steady-state aerobic exercise. Participants completed 2 graded exercise tests (GXT) on a cycle ergometer separated by 30 minutes of steady-state exercise. Blood lactate was measured the last 45 seconds of each stage during both GXTs, whereas EMG of the vastus lateralis was monitored continuously. Individual agreement demonstrated that pre-exercise and post-exercise LT occurred at the same work rate in 2 of 10 participants, whereas EMGT occurred at the same work rate in 6 of 10 participants. Results showed no mean difference between work rates for LT or EMG threshold for the pre-exercise GXT, but LT was significantly lower (p < 0.01) than EMGT during the post-exercise GXT. Post-GXT LT work rates were also determined to be significantly lower than pre-GXT LT (p = 0.034), whereas no differences existed in EMG thresholds. Although both LT and EMGT testing may display similar properties, they are not interchangeable. The physiological responses to increasing exercise intensity between La and EMG signaling seem to be associated, and their interaction may not be cause-effect. Because of poor individual agreement, caution should be used when determining LT through the use of EMG. Further research is needed to determine the ability of these 2 metrics to prescribe training intensities.

Bias varies for bioimpedance analysis and skinfold technique when stratifying collegiate male athletes' fat-free mass hydration levels

This study evaluated the accuracy of bioimpedance analysis (BIA)- and skinfold (SF)-based body fat percentage estimates in collegiate athletes with varying fat-free mass (FFM) hydration levels. Subjects were evaluated as a whole (n = 63) and at FFM hydration levels of 64.00%-68.99% (FFM-Hydration_L1; n = 37) and 69.00%-74.00% (FFM-Hydration_L2; n = 26). Proportional bias was absent in the SF technique when stratifying FFM hydration levels. Contrarily, proportional bias was observed when using BIA for FFM-Hydration_L1, but not in FFM-Hydration_L2. Novelty Fat-free mass hydration levels impact BIA-based body fat estimates more than skinfold-based body fat.

Effects of Active Sitting on Reading and Typing Task Productivity

Increased sedentary behavior and reduced physical activity among children and adults has led to the advent of various active devices to combat these behaviors. Active sitting, consisting of modified chairs or stability balls, allows the body to stay dynamic while seated. While research has evaluated the health benefits of active sitting, minimal research has shown the effects of active sitting on productivity in adult populations. The purpose was to evaluate the effects of various chairs (active versus non-active) on typing and reading task productivity. Twenty adult participants performed typing and reading tasks for 10-minutes while sitting on each of the following: standard chair (SC), stability ball (SB), and active sitting chair (ST). Reading comprehension (RC), words per minute (WPM), accuracy, and errors were measured following each task. Additionally, perceived productivity was measured using a self-reported rating of difficulty scale (1-10). In terms of RC, there was no difference between the chairs (p = 0.16). However, perceived productivity was significantly greater on the SC as compared to SB (p < 0.01) and ST (p < 0.01). For the typing task, no differences were demonstrated for errors (p = 0.87) or accuracy (p = 0.91). However, WPM was significantly greater on SC (38.8 ± 10.5) compared to ST (35.9 ± 9.5) (p = 0.02). For perceived typing productivity, SC and SB demonstrated significantly greater values compared to ST (p < 0.01). Results suggest that various types of active sitting may have a minimal negative effect on workplace performance and perceived productivity.

Cardiovascular and metabolic responses of active sitting while performing work-related tasks

Stability balls and active-balance sitting chairs have recently emerged as a way to reduce sedentary behaviours in office settings. The purpose of this study was to determine differences in caloric expenditure and heart rate between a standard chair (SC), stability ball (SB) and active balanced sitting chair (ST) while performing work-related tasks. Participants (n = 20) performed a 10-minute randomised reading and typing task while sitting on the SC, SB and ST. For both the reading and typing tasks, heart rate (HR), caloric expenditure per minute and metabolic equivalents were all significantly greater (i.e. 6-13%; 19-40%; 18-39%, respectively) while using the ST when compared to the SC and SB. No significant differences were observed between the SB and SC for any of the comparisons. The ST produced a greater HR response and caloric expenditure than the SC or SB, indicating that active balanced sitting may be a feasible way to increase energy expenditure in an office setting. Practitioner summary: The purpose of this study was to determine differences in cardiovascular and metabolic responses to various forms of office chairs. The key finding was that active sitting on a balance chair significantly increased heart rate and caloric expenditure as compared to a stability ball and standard chair. Abbreviations: SC: standard chair; SB: stability ball; ST: active balanced chair; HR: heart rate; kcalmin: caloric expenditure per minute; MET: metabolic equivalents.

Validity of Foot-To-Foot Bioelectrical Impedance for Estimating Body Composition in NCAA Division I Male Athletes: A 3-Compartment Model Comparison

Nickerson, BS, Snarr, RL, and Ryan, GA. Validity of foot-to-foot bioelectrical impedance for estimating body composition in NCAA Division I male athletes: A 3-compartment model comparison. J Strength Cond Res 33(12): 3361-3366, 2019-The purpose of this study was to validate single-frequency foot-to-foot bioelectrical impedance analysis (FF-BIA) against a 3-compartment (3C) model in NCAA Division I male athletes. Thirty-three athletes (football = 19, baseball = 8, basketball = 3, and cheerleading = 3) had body fat percentages (BF%) and fat-free mass (FFM) estimated using a 3C model and FF-BIA. The criterion 3C model was derived from body mass, body volume (air displacement plethysmography), and total body water (bioimpedance spectroscopy). The mean BF% and FFM values for FF-BIA were not statistically significant when compared with the 3C model (p = 0.14 and 0.28, respectively). The standard error of estimate (2.79% and 2.64 kg), total error (2.95% and 2.64 kg), and 95% limits of agreement (±5.67% and ±5.15 kg) were considered acceptable for BF% and FFM, respectively. However, there was a significant trend in the regression line of the Bland-Altman plot, which indicated proportional bias for BF% (r = -0.50; p < 0.01). No proportional bias was present for FFM (r = 0.26; p > 0.05). Foot-to-foot BIA seems to be valid for estimating group and individual athlete's FFM. Similarly, FF-BIA can be used for estimating group BF%. However, proportional bias indicates that FF-BIA is not valid for individual estimates of BF%.

Effects of Heat Exposure on Body Water Assessed using Single-Frequency Bioelectrical Impedance Analysis and Bioimpedance Spectroscopy

The purpose of this study was to determine if heat exposure alters the measures of total body water (TBW), extracellular water (ECW), and intracellular water (ICW) in both single-frequency bioelectrical impedance analysis (BIA) and bioimpedance spectroscopy (BIS). Additionally, we sought to determine if any differences exist between the BIA and BIS techniques before and after brief exposure to heat. Body water was evaluated for twenty men (age=24±4 years) in a thermoneutral environment (22°C) before (PRE) and immediately after (POST) 15 min of passive heating (35°C) in an environmental chamber. The mean difference and 95% limits of agreement at PRE demonstrated that BIS yielded significantly higher body water values than BIA (all p<0.05; TBW=1.8kg; ECW=0.6±1.3kg; ICW=1.2±3.7kg). However, the effect size (ES) of the mean differences at PRE were small and the r-values were high (r≥0.97). TBW and ICW remained significantly higher at POST for BIS (both p<0.05; 1.4±3.2kg and 1.1±3.7kg, respectively) whereas ECW was not different (p>0.05; 0.2±1.5kg). Additionally, the ES of the mean differences at POST were trivial to small and the r-values were high (r≥0.96). When analyzing the changes in body water before and after heat exposure, POST values for BIS were significantly higher than PRE (all p<0.001; TBW=0.6±0.8kg; ECW=0.4±0.3kg; ICW=0.3±0.6kg). Similarly, POST values for BIA were significantly higher than PRE (all p<0.001; TBW=1.0±0.6kg; ECW=0.7±0.4kg; ICW=0.4±0.4kg). BIA and BIS provide similar body water estimates. However, the increase in POST body water values indicate more research is needed before either method can be used for estimating body water after heat exposure.

Electromyographical Comparison of a Traditional, Suspension Device, and Towel Pull-Up

Strengthening muscles of the back may have various implications for improving functions of daily living, aiding in the transfer of power in throwing, and assist in injury prevention of the shoulder complex. While several versions of the pull-up exist, there is currently no literature comparing their differences. The purpose of this investigation was to compare the electromyographical activity of the latissimus dorsi, posterior deltoid, middle trapezius, and biceps brachii while performing three variations of the pull-up. Resistance-trained men and women (n =15, age = 24.87 ± 6.52 years) participated in this study by performing traditional pull-ups, suspension device pull-ups, and towel pull-ups in a randomized fashion. Each pull-up was performed for three repetitions with a 1.5 bi-acromial grip-width for each participant. Normalized (%MVC) electromyographical values were recorded for each muscle group during each pull-up variation. No significant differences existed within the latissimus dorsi, biceps brachii or posterior deltoid between any of the exercises. For the middle trapezius, towel pull-ups provided significantly lower muscle activity than the traditional pull-up, while no differences between suspension pull-ups and the other variations occurred. In conclusion, only one muscular difference existed between the exercise variations and all versions examined provided electromyographical values, determined by current literature, to invoke a sufficient stimulus to promote increases in muscle strength and hypertrophy. Although further research is needed, practitioners can be confident when programming any of the movement variations examined when attempting to elicit adaptations of muscular strength and hypertrophy.

Electromyographical Comparison of Pike Variations Performed With and Without Instability Devices

Snarr, RL, Hallmark, AV, Nickerson, BS, and Esco, MR. Electromyographical comparison of pike variations performed with and without instability devices. J Strength Cond Res 30(12): 3436-3442, 2016-Instability devices are primarily used with the intent of increasing the intensity of traditional exercises by providing further muscular demands of the abdominal wall by decreasing stability. Although there are multiple studies examining these devices, most often they only compare one such device to a stable movement and overlook the comparison among multiple devices. The purpose of this investigation was to compare the electromyographical differences of the rectus abdominis (RA), external oblique (EO), erector spinae (LSES), and rectus femoris (RF) during pike variations performed on various surfaces. Twenty men and women volunteered for this study. All subjects performed 5 variations of a pike on varying surfaces (i.e., stable ground [PK], Swiss ball [SB], suspension training device [ST], BOSU ball [BOSU], and Core Coaster [CC]). Normalized (%MVC) values were recorded for each muscle during 5 repetitions of each pike variations. For the RA, EO, LSES, and RF, the PK elicited significantly lower values compared with the instability devices. In terms of the EO, the ST was significantly higher than the BOSU, SB, and CC. Results of this investigation demonstrated significant differences between the instability devices and the stable pike. These results indicate that with more freely moving instability devices (e.g., suspension device, Swiss ball, etc.), core musculature may require greater muscular demands. Practitioners should take note that traditional stable pikes may not offer a core musculature challenge to resistance-trained individuals.

Comparison of total and segmental body composition using DXA and multifrequency bioimpedance in collegiate female athletes

The purpose of this investigation was to determine the agreement between multifrequency bioelectrical impedance analysis (BIA) and dual-energy x-ray absorptiometry (DXA) for measuring body fat percentage (BF%), fat-free mass (FFM), and total body and segmental lean soft tissue (LST) in collegiate female athletes. Forty-five female athletes (age = 21.2 ± 2.0 years, height = 166.1 ± 7.1 cm, weight = 62.6 ± 9.9 kg) participated in this study. Variables measured through BIA and DXA were as follows: BF%, FFM, and LST of the arms (ARMS(LST)), the legs (LEGS(LST)), the trunk (TRUNK(LST)), and the total body (TOTAL(LST)). Compared with the DXA, the InBody 720 provided significantly lower values for BF% (-3.3%, p < 0.001) and significantly higher values for FFM (2.1 kg, p < 0.001) with limits of agreement (1.96 SD of the mean difference) of ±5.6% for BF% and ±3.7 kg for FFM. No significant differences (p < 0.008) existed between the 2 devices (InBody 720-DXA) for ARMS(LST) (0.05 kg), TRUNK(LST) (0.14 kg), LEGS(LST) (-0.4 kg), and TOTAL(LST) (-0.21 kg). The limits of agreement were ±0.79 kg for ARMS(LST), ±2.62 kg for LEGS(LST), ±3.18 kg for TRUNK(LST), and ±4.23 kg for TOTAL(LST). This study found discrepancies in BF% and FFM between the 2 devices. However, the InBody 720 and DXA appeared to provide excellent agreement for measuring total body and segmental LST. Therefore, the InBody 720 may be a rapid noninvasive method to assess LST in female athletes when DXA is not available.