More than Body Composition: A Darwinian Theory of Somatotype Applied to a DII Track and Field Outdoor Season.

This study presents somatotype data on a team sport with chronic and diverse sporting demands. The aims were to (1) characterize a somatotype profile for Division II (DII) track and field athletes (n=54) by sex, class, and events; (2) determine if somatotype changed across the season; (3) determine if changes differed based on class or sex; and, (4) assess potential differences in somatotype between sexes. Methods: Anthropometrics (height, weight, body composition, somatotype) were evaluated after a competitive indoor season and immediately before the outdoor conference championships (41 days). Body measurements were assessed using a bioelectrical impedance analysis device, skinfold assessment, boney breadths, and limb girths. Descriptive statistics are provided as well as results from two-way ANOVAs which evaluate differences in actual and change scores across sex and class. Results: Our DII track and field athletes were primarily endomorphic (scores displayed as ENDO, MESO, ECTO, respectively). Males were found to be primarily ENDO-MESO somatotypes (4.7, 4.1, 3.0), while females were dominantly ENDO (7.7, 2.9, 2.9). Upperclass were more ENDO-MESO balanced compared with lowerclass (5.8, 3.8, 2.8 vs 6.0, 3.5, 3.0). When investigated based on sex, class level, and event, the groups were similar. There was no meaningful change to ECTO scores across the season for males or females. Female athletes improved ENDO scores (-0.89%) and males and females improved MESO scores (14.29% and 5.29%, respectively), indicating adaptations can be accomplished despite the chronic demands of a competitive season. Conclusion: Our research offers practitioners information about the potential changes they may expect across a competitive track and field season.

Differences in Lift Quality During the Barbell Back Squat When Using Perceived Recovery Status-Regulated Intrasession Recovery Compared With Standardized Recovery Intervals.

ABSTRACT: Wolfe, AA, Laurent, CM, Tolusso, DV, and Rinehart, AN. Differences in lift quality during the barbell back squat when using perceived recovery status-regulated intrasession recovery compared with standardized recovery intervals. J Strength Cond Res 38(3): 444-449, 2024-The current investigation examined kinetic differences between standardized and perceptually regulated rest internals during power-based resistance training. Recreationally resistance-trained men ( n = 7) and women ( n = 7) completed 3 training sessions. Session 1 consisted of barbell back squat (SQ) 1 repetition maximum (1RM) testing. Two counterbalanced subsequent sessions of perceptually regulated vs. standardized intrasession recovery for 5 sets of 6 repetitions of SQ at 80% 1RM were completed. Lift quality was assessed using a barbell accelerometer that measured concentric and eccentric power and force outputs for each repetition. In each set, subjects reported a rating of perceived exertion (RPE) followed by passive rest for either 2 minutes or a self-selected period using the Perceived Recovery Status (PRS) scale. For the self-selected session, when an individual reported a PRS at level "7," they were instructed to begin the next set. Data were analyzed using a 2 (session) × 5 (set) repeated-measures ANOVA with Bonferroni post hoc analyses performed when appropriate. No significant main effects or interactions were observed for any set quality metrics in the concentric phase or eccentric phase, except peak eccentric power ( p = 0.01). Post hoc analyses revealed a significant increase in peak eccentric power from set 1 to set 2 ( p = 0.003) only. Finally, no significant difference between self-selected vs. standardized work-to-rest strategies on RPE ( p = 0.547) was expressed. These data suggest perceptually regulated intrasession recovery selection yields equivalent lift quality as standardized rest recommendations. Therefore, PRS utilization may provide a more simplified and individualized method of between-set rest prescriptions.

The Validity of Perceptual Recovery Status on Monitoring Recovery During a High-Intensity Back-Squat Session.

Adaptations to resistance training and subsequent performance can be undermined by inadequate interset recovery. Methods typically used to monitor recovery were developed for longitudinal use, making them time-inefficient within singular exercise bouts. If valid, perceptual recovery status (PRS) may be used as an efficient and inexpensive assessment tool to monitor individual recovery. PURPOSE: The aim of this study was to assess the validity of PRS on monitoring recovery during a high-intensity back-squat session. METHODS: Ten healthy men participated in the 2-session study (separated by at least 48 h). Session 1 included anthropometrics, PRS familiarization, and a 1-repetition-maximum back squat. Session 2 included a high-intensity protocol (5 sets of 5 repetitions; 5-min interset recovery; 85% of 1-repetition maximum). PRS was obtained before the first set and during the last 30 seconds of each 5-minute recovery; rating of perceived exertion (RPE) was also collected. A linear position transducer collected mean barbell velocity (MBV). Repeated-measures correlations assessed the common intraindividual relationships of PRS scores to intraset MBV and RPE, respectively. RESULTS: A very large, positive correlation appeared between PRS and MBV (r [95% CI] = .778 [.613 to .878]; P < .0001). A large, negative correlation emerged between PRS and RPE (r [95% CI] = -.549 [-.737 to -.282]; P < .001). CONCLUSIONS: Results indicate that PRS can be a means for practitioners to monitor individualized recovery. PRS tracked well with RPE, strengthening its utility in a practitioner-based setting. Findings provide insight into the practicality of PRS for recovery monitoring. It could be used alongside other measures (eg, MBV and countermovement jump) to individually program and maintain performance.

Effects of Different Surfaces on Metabolic Cost During Repetitive Jumping: A Pilot Study.

The purpose of this pilot study was to determine if there is a difference in metabolic cost when jumping on platforms of varying thickness, as well as whether a difference exists in metabolic cost between genders exists on the different platforms. Fourteen participants (seven males and seven females) completed three repetitive jumping trials on the DigiJump machine. Each trial was performed at a cadence of 120 jumps per minute and at a minimum height of 1/2″ per jump. Trials were completed on platforms of 1/2″, 3/8″, and 1/4″ thickness. Participants were instructed to jump as long as possible while maintaining the prescribed cadence or until fifteen minutes had elapsed. There were no differences observed in metabolic cost or exertion for all participants or between genders as indicated by oxygen consumption, respiratory exchange ratio, upper leg RPE, or lower leg RPE. There were also no differences for durations of exercise the participants were able to sustain on the machine. However, when comparing data between genders, a significant interaction was observed in total body RPE across the three platforms (p = .009) and in HR on the 1/2″ platform (p = .018). Results from this study indicate that metabolic cost is similar during repetitive jumping regardless of platform rigidity or gender. However, post-trial comments from participants did show preferences towards specific platforms, though this was not apparent in exercise duration.

A Pilot Study on Cannabidiol (CBD) and Eccentric Exercise: Impact on Inflammation, Performance, and Pain.

Cannabidiol (CBD) is a non-psychoactive cannabinoid purported to reduce symptoms of discomfort. Individuals are now using CBD to treat symptoms of multiple sclerosis, seizures, and chronic pain. Animal models indicate that CBD may be effective at reducing inflammation post fatiguing exercise. However, little evidence is available to evaluate these findings in humans. Therefore, the purpose of this investigation was to evaluate the impact of two doses of CBD oil on inflammation (IL-6), performance, and pain after an eccentric loading protocol. Participants (n = 4) participated in three conditions (placebo, low dose, and high dose), in this randomized, counterbalanced design. Each condition took 72 hours to complete, with a 1-week washout period between conditions. At the beginning of each week, participants were subjected to a loading protocol of six sets of ten eccentric only repetitions in the single-arm bicep curl. Participants consumed capsules of either a placebo, low dose (2mg/kg) or high dose (10mg/kg) of CBD oil immediately following the session and continued every twelve hours for 48 hours. Venipunctures were taken before exercise and repeated at 24, 48, and 72 hours post exercise. Blood samples were centrifuged for 15 minutes in gel and lithium heparin vacutainers. Plasma was separated from cells and stored at -80° until analysis. Samples were analyzed using an immunometric assay for IL-6 (ELISA). Data were analyzed using a three (condition) by four (time) repeated measure ANOVA. There were no differences in inflammation between conditions (F(2,6) = 0.726, p = 0.522, np 2 = 0.195) or across time (F(3,9) = 0.752, p = 0.548, np 2 = 0.200), handgrip strength between conditions (F(2,6) = 0.542, p = 0.607, np 2 = .153) or across time (F(3,9) = 2.235, p = .153, np 2 = .427), or bicep curl strength between conditions (F(2,6) = 0.675, p = 0.554, np 2 = .184) or across time (F(3,9) = 3.513, p = .150, np 2 = .539). There were no differences in pain between conditions (F(2,6) = 0.495, p = 0.633, np 2 = .142), but there was a difference across time (F(3,9) = 7.028, p = .010, np 2 = .701). There were no significant interactions to note. Although there was no statistical significance between conditions (likely due to the low sample size), there was a visible increase in IL-6 48 (4.88 ± 6.53) and 72 hours (3.12 ± 4.26) post exercise in the placebo condition which was not observed in the low (48: 0.35 ± 2.22; 72: 1.34 ± 5.6) and high dose condition (48: 1.34 ± 1.34; 72: -0.79 ± 5.34). Future investigations should consider implementing eccentric resistance training across a larger portion of the body to improve ecological validity of the exercise. A larger sample would reduce risk of researchers committing a type II statistical error and give strength to detecting differences between conditions.

Eccentric resistance training with neurological conditions: A meta analysis.

BACKGROUND: People with neurological conditions are exposed to muscle wasting resulting in reduced strength and endurance. Both deficiencies negatively impact gait and balance, each of which can be benefited by strengthening exercises. Unfortunately, people with neurological conditions often do not have the ability to perform traditional weight training as their endurance and strength fail to meet the minimum threshold for improvement. An alternative to traditional, full range of motion lifting is eccentric resistance training (ERT). RESEARCH QUESTION: The current systematic review and meta-analysis sought to evaluate the efficacy of ERT against conventional therapeutic modalities or weightlifting on walking speed, Timed Up and Go (TUG), and maximum voluntary isometric contraction (MVIC) in individuals with neurological conditions. METHODS: Web of Science, PubMed, and Academic Search Complete were searched until September 1, 2020, followed by a manual search on December 3, 2021. Publications were included if they were peer reviewed, available in English, consisted of a pre-specified neurological disorder, involved human subjects, had an eccentric and "traditional" therapy; and reported at least one of the outcome measures at both pre- and post-intervention. RESULTS: Thirteen studies of human subjects (n = 297) and 47 standardized mean differences (SMD) were included in the multilevel model analysis. The analysis revealed a small, albeit non-significant effect on performance (TUG, MVIC, walking speed) when comparing traditional therapies and ERT (SMD: 0.136; 96; 95 % CI: -0.0002, 0.050). SIGNIFICANCE: There appears to be no difference between ERT and traditional therapy or weightlifting on measured outcomes. In this way, ERT is as effective as traditional therapeutics and full range of motion weightlifting to improve movement in clinical populations. Practitioners working with populations with neurological conditions may consider supplementing or replacing traditional strengthening activities with ERT as clients can complete greater volumes of work with lower metabolic demand.

A VO2max Protocol for Young, Apparently Healthy Adults.

The Bruce and Astrand treadmill protocols are commonly utilized when assessing maximal oxygen consumption (VO2max). However, the steep grade implemented in the protocols often leads to localized muscular fatigue, potentially causing participants prematurely to terminate the test prior to reaching their true VO2max. The purpose of this study was to evaluate a Novel VO2max protocol that may be better suited for young, apparently healthy populations. The Novel protocol starts at a higher speed and lower initial grade to limit lower extremity fatigue. Fifteen participants performed the Bruce, Astrand, and Novel protocols with the following maximal values recorded from each: VO2max, maximal ventilation (VEmax), respiratory exchange ratio (RER), heart rate (HR), rating of perceived exertion (RPE) and time to exhaustion (TTE). The Novel protocol displayed substantial agreement with both criterion protocols. Mean absolute percent error (MAPE) was less than 10% indicating that the Novel protocol is a valid measurement for VO2max values. Bland-Altman analysis revealed that the Novel protocol exhibited a low degree of bias, with tight limits of agreement when compared to the Bruce (bias ±95% LOA = 0.824 ± 3.163) and Astrand protocols (-0.153 ± 3.528) for VO2max. A paired samples t-test revealed no significant differences between Novel and criterion protocols for VO2max. Paired samples t-tests revealed that the Novel protocol had significantly lower TTE when compared to the Bruce and Astrand protocols and produced similar VO2max values to that of the Bruce and Astrand. The Novel protocol may be considered a valid and time-efficient protocol.

The Validity of Perceived Recovery Status as a Marker of Daily Recovery Following a High-Volume Back-Squat Protocol.

Although a variety of tools to monitor recovery have been developed, many are impractical for daily use due to cost, time, and challenges with interpretation. The Perceived Recovery Status (PRS) scale was recently developed as an expeditious, noninvasive tool to assess recovery status. While PRS has been strongly associated with repeated sprinting performance, a paucity of research exists relating PRS and performance recovery following resistance exercise. PURPOSE: The purpose of this study was to evaluate the sensitivity of PRS as a subjective marker of recovery up to 72 hours after a high-volume back-squat protocol. METHODS: Eleven resistance-trained men reported to the laboratory on 5 separate occasions (1 familiarization session and 4 testing sessions). The first testing session was considered the baseline session and consisted of a nonfatiguing performance assessment (ie, countermovement jumps and back squats) and a fatiguing back-squat protocol of 8 sets of 10 at 70% 1-repetition maximum separated by 2 minutes of recovery. Participants returned 24, 48, and 72 hours following baseline to provide a PRS rating and complete the performance assessment. RESULTS: Repeated-measures correlations revealed strong associations between PRS countermovement jump (r = .84) and mean bar velocity (r = .80) (both P < .001). CONCLUSIONS: The current findings suggest that PRS can be used as a method to effectively assess daily recovery following a fatiguing bout of resistance exercise. Practitioners are cautioned that the relationship between PRS and performance recovery is individualized, and equivalent PRS scores between individuals are not indicative of similar recovery.

Prenatal Yoga and Mental Health During the COVID-19 Pandemic: A Randomized-Control Trial.

Studies have demonstrated that new and expectant mothers experience increased levels of stress and anxiety during the COVID-19 pandemic. Though prenatal yoga is an effective mode of improving mental health during pregnancy, no research has evaluated its effect on mental health during times of extreme stress, such as a global pandemic. The purpose of this study was to determine the influence of a single session and a 10-week prenatal yoga intervention on the mental health of pregnant women during the COVID-19 pandemic. Women (n = 19; 28.52 ± 3.74 years; 20.94 ± 4.69 weeks gestation; BMI 29.33 ± 9.08) were randomized into a yoga or a non-yoga control group. There were no differences in demographic factors or depression/anxiety scores between groups at baseline. Baseline levels of anxiety and depression were high, with an average depression score of 8.10 ± 4.85 (scores > 8 represent possible depression) and an average anxiety score of 39.26 ± 12.99 (scores ≥ 39 represent a clinically significant anxiety). After just one session of yoga, women reported feeling less depressed (p = 0.028), tense (p < 0.001), and fatigued (p = 0.004). After 10 weeks, the yoga group had lower anxiety (p = 0.002), depression (p = 0.032), and total mood disturbance (p = 0.002) scores when compared to the control group. Yoga appears to benefit the mental health of expectant mothers, even in times of extreme stress. The findings of this study provide clinicians with valuable information regarding alternative exercise options for mental health during pregnancy during the COVID-19 pandemic.

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.

Profiles of Heart Rate Variability and Bar Velocity after Resistance Exercise.

INTRODUCTION: The aim of this investigation was to observe the association in the time course in recovery between multiple heart rate variability (HRV) metrics and neuromuscular performance, as assessed by mean bar velocity (BVM) in the back squat, over a 72-h period after an exhaustive back squat protocol. METHODS: Eight resistance-trained males completed five laboratory visits within a 7-d period. The first visit involved short-term HRV recordings followed by a familiarization of BVM procedures and a one-repetition maximum test of the back squat. Forty-eight hours later, participants returned to the laboratory for prestimulus measurements, immediately followed by a back squat protocol (8 sets of 10 repetitions at 70% of one-repetition maximum with a 2-min rest). The HRV and the BVM measurements were replicated at 0.5, 24, 48, and 72 h after squat protocol. A multivariate profile analysis and repeated-measures correlation between recovery scores [(new/prestimulus) × 100] for each HRV metric and BVM was computed. RESULTS: All log-transformed (ln) HRV metrics, except low frequency (lnLF) (P = 0.051), had a significant interaction with BVM over time (P < 0.05), indicating that recovery scores in BVM and HRV were not parallel. In addition, recovery scores in all HRV metrics significantly differed from BVM (P < 0.05) in at least one time point across the 72-h period. Furthermore, repeated-measures correlation analysis indicated a lack of intraindividual association (P > 0.05) between the change in BVM and all HRV measurements over time. CONCLUSION: The time course in recovery in HRV measurements after an exhaustive bout of lower-body resistance exercise was not associated with neuromuscular performance recovery.

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.

Effect of Postactivation Potentiation on Explosive Vertical Jump: A Systematic Review and Meta-Analysis.

Dobbs, WC, Tolusso, DV, Fedewa, MV, and Esco, MR. Effect of postactivation potentiation on explosive vertical jump: a systematic review and meta-analysis. J Strength Cond Res 33(7): 2009-2018, 2019-The primary aim of this systematic review and meta-analysis was to quantify the magnitude of the effect of postactivation potentiation (PAP) on explosive vertical power while accounting for the nesting of multiple effects within each study. This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Statement (PRISMA). Original research articles published by January 18, 2018, were located using an electronic search of 4 databases and yielded 759 original publications. Data were extracted and independently coded by 2 authors (W.C.D. and D.V.T.). The standardized mean effect size (ES) was calculated by subtracting the pre-treatment mean from the post-treatment mean and dividing by the pooled SD, adjusting for small sample bias. Multilevel random-effects model was used to aggregate a mean ES and 95% confidence interval (CI) for PAP on vertical jump performance. The cumulative results of 179 effects gathered from 36 studies indicate that PAP does not improve vertical jump performance (ES = 0.08, 95% CI -0.04 to 0.21, p = 0.197), with moderate heterogeneity. Moderator analysis indicated that rest intervals between 3 and 7 minutes provided favorable performance outcomes (ES = 0.18, 95% CI 0.05 to 0.31, p = 0.007). Conversely, rest intervals less than 3 minutes (ES = -0.15, 95% CI -0.31 to 0.01, p = 0.052) or performing isometric contractions (ES = -0.52, 95% CI -0.89 to -0.14, p = 0.007) may be detrimental to performance. Meta-regression indicated that rest interval was the only moderator significantly associated with ES (ß = -0.04, 95% CI -0.57 to -0.02, R = 14.31%, p < 0.001). When appropriate PAP guidelines are followed, an increase in vertical jump performance may be achieved.

The Predictability of Peak Oxygen Consumption Using Submaximal Ratings of Perceived Exertion in Adolescents.

Rating of perceived exertion (RPE) extrapolation involves mathematically extending the submaximal relationship between RPE and oxygen consumption (VO2) to maximal intensity. This technique allows practitioners to forego, potentially dangerous, maximal exertion testing while attaining accurate measures of maximal oxygen consumption used for exercise prescription. This method has been proven accurate in adults, but much less in known when applied to an adolescent population. The purpose of this study was to assess the accuracy of the RPE extrapolation as method for estimating VO2max in adolescents. Twenty-two healthy, asymptomatic adolescents performed a graded exercise test (GXT) to exhaustion. Heart rate and VO2 were recorded throughout the bout with RPE being queried every two minutes using the Borg (6-20) RPE scale. Individual regression lines were fitted for each subject using RPE and VO2 for RPE values up to 13,15, and 17. Theoretical maximal RPE values of 20 and 19 were entered into the equation to calculate an estimated VO2max. Repeated measures ANOVA with planned contrasts showed that all VO2max estimation methods significantly overpredicted measured VO2max (p < .001). Error analysis via Bland-Altman plots revealed large limits of agreement between the all methods, indicating large variability in error between estimated and measured VO2max. The results suggest that submaximal RPE values using the Borg scale cannot be used to predict VO2max in children due to the amount of error in the prediction equations. These inaccuracies could lead to potential under or over-prescription of exercise intensity and adverse effects on the person's health.

A Comparison of Both Motorized and Nonmotorized Treadmill Gait Kinematics to Overground Locomotion.

CONTEXT: Motorized treadmills (MTs) present an altered motor task compared to overground (OG) locomotion in that MT belt surfaces are motor-driven, whereas individuals walking/running OG must propel themselves. A possible solution may lie with novel nonmotorized treadmill (NMT) devices as the belt surface is propelled by the user. OBJECTIVE: The purpose of this study was to compare gait performance during both MT and NMT locomotion to OG. DESIGN: Crossover study. SETTING: A university research laboratory. PATIENTS: A total of 20 healthy adults (10 women) participated in the study. INTERVENTION: Each participant performed self-selected walking and running OG, and on both an MT and NMT. MAIN OUTCOME MEASURE: Shoulder, trunk, and lower-extremity kinematics were analyzed for each treadmill condition and compared to OG. RESULTS: The analyses demonstrated that there were no differences between MT and OG gait kinematics during either walking or running. However, NMT gait showed increased hip, knee, and ankle flexions in late swing and early stance compared to OG during both walking and running. For example, during walking, the NMT elicited hip-, knee-, and ankle-flexion/extension angles of 34.7°, 8.0°, and 3.6° at foot strike compared to 24.8°, -3.1°, and -5.8° in the OG condition (P < .05). There was also a significant reduction in trunk-flexion/extension range of motion during running compared to OG (7.7° in NMT vs 9.8° in OG). CONCLUSIONS: These differences may have implications for both training and rehabilitation on an NMT. Future studies should consider the influence of NMT familiarization on gait performance and should emphasize the assessment of neuromuscular performance.

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.

Comparison of Periodized and Non-Periodized Resistance Training on Maximal Strength: A Meta-Analysis.

BACKGROUND: Periodization is a logical method of organizing training into sequential phases and cyclical time periods in order to increase the potential for achieving specific performance goals while minimizing the potential for overtraining. Periodized resistance training plans are proposed to be superior to non-periodized training plans for enhancing maximal strength. OBJECTIVE: The primary aim of this study was to examine the previous literature comparing periodized resistance training plans to non-periodized resistance training plans and determine a quantitative estimate of effect on maximal strength. METHODS: All studies included in the meta-analysis met the following inclusion criteria: (1) peer-reviewed publication; (2) published in English; (3) comparison of a periodized resistance training group to a non-periodized resistance training group; (4) maximal strength measured by 1-repetition maximum (1RM) squat, bench press, or leg press. Data were extracted and independently coded by two authors. Random-effects models were used to aggregate a mean effect size (ES), 95% confidence intervals (CIs) and potential moderators. RESULTS: The cumulative results of 81 effects gathered from 18 studies published between 1988 and 2015 indicated that the magnitude of improvement in 1RM following periodized resistance training was greater than non-periodized resistance training (ES = 0.43, 95% CI 0.27-0.58; P < 0.001). Periodization model (ß = 0.51; P = 0.0010), training status (ß = -0.59; P = 0.0305), study length (ß = 0.03; P = 0.0067), and training frequency (ß = 0.46; P = 0.0123) were associated with a change in 1RM. These results indicate that undulating programs were more favorable for strength gains. Improvements in 1RM were greater among untrained participants. Additionally, higher training frequency and longer study length were associated with larger improvements in 1RM. CONCLUSION: These results suggest that periodized resistance training plans have a moderate effect on 1RM compared to non-periodized training plans. Variation in training stimuli appears to be vital for increasing maximal strength, and longer periods of higher training frequency may be preferred.

Placebo Effect: Influence on Repeated Intermittent Sprint Performance on Consecutive Days.

Despite the available literature addressing the placebo effect's role in mediating human performance, there is a paucity of research addressing the possibility of a placebo effect both within and between bouts of repeated sprint performance on consecutive days. Therefore, the purpose of this study was to determine whether the administration of a placebo influences recovery during sessions of intermittent sprinting. Ten subjects performed 4 repeated sprint tests under 2 different conditions; 2 while being administered a control beverage separated by 24 hours of recovery and the other 2 with a placebo beverage separated by 24 hours of recovery. Before each sprint test, subjects provided perceived recovery status (PRS). Ratings of perceived exertion were recorded within 5 seconds after each sprint. After each repeated sprint protocol, subjects were asked to provide a rating of perceived exertion (RPE), rate their pain, and provided a blood lactate sample. Power was recorded throughout each session from a nonmotorized treadmill to analyze changes in sprinting performance. Repeated-measures analysis of variance was used to determine significant differences in peak and mean power, PRS, RPE, pain, and blood lactate. The placebo trial produced significantly higher peak (p < 0.001) and mean power (p = 0.002) vs. the control in later sprints absent of any other significant difference in metabolic or perceptual strain (p > 0.05). In conclusion, it seems that the administration of a placebo can attenuate the decline in performance as fatigue increases during repeated sprinting bouts.