Changes in Dynamic Balance Ability Among Firefighter Recruits: A Longitudinal Cohort Study.

ABSTRACT: Cornell, DJ, Gnacinski, SL, and Ebersole, KT. Changes in dynamic balance ability among firefighter recruits: A longitudinal cohort study. J Strength Cond Res 38(4): 734-741, 2024-It has been suggested that enhanced balance ability may mitigate the high musculoskeletal injury (MSKI) rate among firefighters, but the longitudinal changes in dynamic balance ability within this tactical athlete population have yet to be characterized. The purpose of this study was to examine the changes in dynamic balance ability of a cohort population of firefighter recruits completing a training academy and their probationary period as active-duty firefighters. Twenty-seven male firefighter recruits completed the modified Star Excursion Balance Test (mSEBT) at the beginning (W1) and at the end of their training academy (W14) and after completing their probationary period as active-duty firefighters (W38). After controlling for age and changes in body fat (BF) over time, significant changes in mSEBTANT ( p < 0.001), mSEBTPL ( p = 0.015), mSEBTPM ( p < 0.001), and mSEBTCOMP ( p = 0.003) were observed across time. Although mSEBTPL performance significantly increased ( p = 0.033) in from W1 to W14, significant decreases in all mSEBT reach directions were observed from W14 to W38 ( p < 0.05), with mSEBTANT ( p < 0.001) and mSEBTCOMP ( p = 0.002) also significantly decreasing from W1 to W38. However, the frequency of right vs. left asymmetries (>4 cm) did not significantly change over time in any mSEBT reach direction ( p > 0.05). Irrespective of age or changes in BF, minimal changes in the dynamic balance ability of firefighter recruits were observed during their training academy, but significant decreases in balance ability were noted by the end of their probationary period.

Standing Pelvic Tilt Is Associated With Dynamic Pelvic Tilt During Running When Measured by 3-Dimensional Motion Capture.

Standing pelvic tilt (PT) is related to biomechanics linked with increased risk of injury such as dynamic knee valgus. However, there is limited evidence on how standing PT relates to dynamic PT and whether the palpation meter (PALM), a tool to measure standing PT, is valid against 3-dimensional (3D) motion analysis. The purposes of this study were to (1) determine the criterion validity of the PALM for measuring standing PT and (2) identify the relationship between standing PT and dynamic PT during running. Participants (n = 25; 10 males and 15 females) had their standing PT measured by the PALM and 3D motion analysis. Dynamic PT variables were defined at initial contact and toe off. No relationship between the 2 tools was found. Significant large positive relationships between standing PT and PT at initial contact (r = .751, N = 25, P < .001) and PT at toe off (r = .761, N = 25, P < .001) were found. Since no relationship was found between standing PT measured by the PALM and 3D motion analysis, the PALM is not a valid alternative to 3D motion analysis. Clinicians may be able to measure standing PT and gain valuable information on dynamic PT, allowing clinicians to quickly assess whether further biomechanical testing is needed.

Body Composition Is Related to Maximal Effort Treadmill Test Time in Firefighters.

Firefighting tasks may require near maximal levels of cardiorespiratory fitness. Previous research has indicated that body fat percentage (BF%) and aerobic capacity (VO2peak) are related to the performance of firefighting tasks. Since a standard submaximal treadmill test for firefighters is terminated at 85% of maximal heart rate (MHR), key performance information relating to maximal cardiorespiratory effort may not be measured in a submaximal test. The purpose of this study was to examine the relationships between body composition and time spent running at intensities greater that 85% MHR. Height, weight, body mass index (BMI; kg/m2), BF%, MHR (bpm), VO2peak (mL/kg/min), predicted VO2peak (P-VO2peak; mL/kg/min), submaximal treadmill test time (WFIsub Test Time; min), and maximal treadmill test time (WFImax Test Time; min) were collected in fifteen active-duty firefighters. The results indicated that significant relationships (p < 0.05) existed between BF% and VO2peak, BF% and WFImax Test Time, BF% and Tdiff, and VO2peak and WFImax Test Time. P-VO2peak was not significantly different than VO2peak, and the WFImax Test Time was significantly longer than the WFIsub Test Time. These results indicate that a submaximal treadmill test may reasonably predict VO2peak, but key information about physiological work at intensities greater than 85% MHR may be missed when using submaximal effort tests.

Autonomic Nervous System Response to Far-Infrared Sauna Exposure in Firefighters.

OBJECTIVES: Fire departments have employed far-infrared sauna (FIRS) use as part of post-fire call protocols to address concerns related to carcinogens. The inability of the autonomic nervous system (ANS) to fully recover following an emergency call, as demonstrated by heightened sympathetic nervous system activity and delayed parasympathetic nervous system reactivation, has been implicated as a potential factor related to sudden cardiac death. The use of a sauna post-fire call, which has been demonstrated to elevate body temperature, may interfere with the ability of the ANS to fully recover. The purpose of this study was to examine ANS responses to FIRS exposure in firefighters (FFs) with (EX) and without (NONEX) prior maximal exercise. METHODS: Sixteen career FFs participated in this study. Body temperature (TEMP), heart rate (HR), heart rate variability (HRV), blood pressure (BP), and blood lactate (La─) were measured at the start of each testing session, following a maximal exercise test (EX only), and immediately after a 15-min FIRS exposure for NONEX and EX. RESULTS: In NONEX, TEMP increased (P < 0.001); however, there was no change in HR, HRV, BP, or La─. In EX, BP remained unchanged while TEMP, HR, and La─ were significantly (P < 0.001) greater than baseline following FIRS exposure and HRV was significantly (P = 0.018) lower than baseline. CONCLUSIONS: These findings indicate that FIRS following maximal exercise did support some ANS recovery, but may interfere with restoration of body temperature and parasympathetic nervous system reactivation, potentially influencing post-call cardiovascular risk in FFs.

Functional Movement Quality of Firefighter Recruits: Longitudinal Changes from the Academy to Active-Duty Status.

Approximately half of the injuries experienced by firefighters consist of musculoskeletal injuries (MSKIs). Functional movement quality may be associated with MSKI risk within this tactical athlete population. Previous research indicates that measures of body composition change among firefighter recruits progressing from academy training through active-duty service, but similar changes in functional movement quality have yet to be examined. The purpose of this study was to describe longitudinal changes in functional movement quality of firefighter recruits. Body mass index (BMI), body fat (BF), and Functional Movement Screen (FMS) data were collected from 26 male firefighter recruits at the onset (W1) and completion (W14) of their training academy, and at the completion of their probationary period of active-duty service (W38). After adjusting for changes in BMI and BF across time, significant changes (ps < 0.05) in Composite FMS scores were identified, with significant increases in from W1 to W14 and from W14 to W38, as well as an overall increase from W1 to W38. These results suggest that the development of firefighter-specific skills can decrease the MSKI risk of firefighter recruits by facilitating enhanced functional movement competencies, particularly during tasks that require single-leg movement and core strength and stability.

Relationships between balance and physical fitness variables in firefighter recruits.

BACKGROUND: Research has suggested that balance ability contributes to musculoskeletal injury (MSKI) rates in firefighters. Though the Y-Balance Test (YBT) can predict injury, it is unclear what physical measures inform YBT performance in firefighters. Thus, there is a lack of knowledge regarding best practice for improving balance in firefighters. OBJECTIVE: To evaluate the relationship between the YBT and fitness measures, including body composition, aerobic capacity, functional total-body power, upper and lower-body strength, and movement efficiency, among firefighters. METHODS: Dynamic balance (YBT), body mass index (BMI), body-fat percentage (BF%), fat free mass (FFM), aerobic capacity (VO2max), stair climb (SC), upper (1RMbench) and lower-body (1RMsquat) strength, and Fusionetics™ Movement Efficiency Screen (ME) measures were collected among 35 firefighter recruits. Pearson correlation coefficients were used to examine relationships between YBT and the performance measures. RESULTS: Dynamic balance ability in firefighter recruits is significantly (p < 0.05) related to BMI, lower-body strength, and movement quality, but not with aerobic capacity, stair climb performance, and upper body strength. CONCLUSIONS: Greater YBT performance in firefighter recruits is associated with lower BMI, greater functional movement, and greater lower-body strength. Future research is warranted to incorporate these elements into balance training programs for firefighter recruits.

Heart rate response to alarm tones in firefighters.

OBJECTIVE: To examine cardiovascular responses to medical (MED) and fire (FIRE) alarm tones in firefighters. METHODS: Heart rate was collected throughout 24-h shifts (N = 41). Call logs were utilized post hoc to identify heart rate at the time the alarm sounded (TIMETONE), peak heart rate following the alarm (TIMEPEAK), and heart rate at the time of station departure (TIMEDEPART) for MED and FIRE calls. A 2X3 (TONE x TIME) split-plot mixed-model repeated-measures analysis of variance (ANOVA) and least significant differences tests examined the influence of tone type on heart rate, expressed as a percent of age estimated maximum. Bivariate Pearson correlations examined the relationship between body mass index (BMI) and TIMEPEAK and TIMEDEPART. An alpha of 0.05 determined statistical significance and Bonferroni Corrections were applied to post hoc comparisons (p < 0.017). RESULTS: Follow-up analyses for the significant 2 × 3 repeated-measures ANOVA (p = 0.035) indicated differences in heart rate for MED (p < 0.001) and FIRE (p < 0.001) where TIMETONE < TIMEPEAK, TIMETONE < TIMEDEPART, and TIMEPEAK > TIMEDEPART. There was a non-significant simple effect of time for MED and FIRE at TIMETONE (p = 0.259), but significant effects of tone type where FIRE > MED at TIMEPEAK (p < 0.001) and TIMEDEPART (p = 0.002). There was a significant small positive relationship between BMI and TIMEPEAK (p = 0.002) and TIMEDEPART (p < 0.001) for MED only. CONCLUSIONS: Alarms increased heart rates to a greater extent in FIRE than MED calls. Higher BMI was related to greater heart rate responses in MED but was unrelated to FIRE response.

Influence of Body Composition on Post-Exercise Parasympathetic Reactivation of Firefighter Recruits.

Firefighters have a sustained risk for experiencing a sudden cardiac event after completing a fire call. Heart rate recovery (HRR) can be utilized to characterize autonomic nervous system (ANS) recovery and has been linked to cardiac events. Research suggests that body composition influences post-exercise HRR responses in non-firefighter populations. The purpose of this study was to examine the influence of body mass index (BMI), waist circumference (WC), and percent body fat (BF) on the HRR response of firefighter recruits. BMI (kg·m-2), WC (cm), and BF (%) data from 57 firefighter recruits were collected. HRR (b·min-1) data were collected at completion (HR0), as well as 15 (HR15), 30 (HR30), 45 (HR45), 60 (HR60), 120 (HR120), and 180 (HR180) seconds following a submaximal step test, and commonly utilized clinical HRR indices were calculated (ΔHRR30, ΔHRR60, ΔHRR120, and ΔHRR180). After controlling for sex, linear mixed regression models did not identify significant interactions between body composition (ps > 0.05) and HRR response across time. However, significant (ps < 0.05) indirect semi-partial correlations were identified between BF and ΔHRR30 (rsp = -0.31) and ΔHRR60 (rsp = -0.27), respectively. Reducing overall BF (vs. BMI or WC) should be prioritized to improve the post-exercise ANS recovery of firefighter recruits.

Influence of a Training Academy on the Parasympathetic Nervous System Reactivation of Firefighter Recruits-An Observational Cohort Study.

Sudden cardiac death (SCD) is the leading type of line-of-duty death among firefighters. An inability to restore parasympathetic nervous system (PSNS) control after activity is associated with SCD. Post-exercise heart rate recovery (HRR) provides unique insight into reactivation of the PSNS. Thus, the purpose of this study was to examine longitudinal changes in HRR responses of 25 male firefighter recruits. HR data were collected after submaximal exercise at week 1 (W1), week 6 (W6), and week 15 (W15) of their training at an academy. Percent maximal heart rate (%MHR) measures were computed at each HRR time point (%MHR0, %MHR15, %MHR30, %MHR45, %MHR60, %MHR120, %MHR180) and absolute HRR values were calculated at 30 s (ΔHRR30), 60 s (ΔHRR60), 120 s (ΔHRR120), and 180 s (ΔHRR180). After controlling for age and percent body fat, there was no statistically significant interaction between Week × HRR (p = 0.730), and there were no changes in ΔHRR30, ΔHRR60, and ΔHRR120, and ΔHRR180 indices across time. However, %MHR at W6 and W15 was significantly lower than %MHR at W1 at every HRR time point (ps < 0.001). Therefore, although the firefighter recruit training academy elicited positive training adaptations, changes in PSNS reactivation after submaximal activity were not identified.

INFLUENCE OF AN ACUTE BOUT OF SELF-MYOFASCIAL RELEASE ON KNEE EXTENSION FORCE OUTPUT AND ELECTRO-MECHANICAL ACTIVATION OF THE QUADRICEPS.

BACKGROUND: In contrast to static stretching (SS), previous research has demonstrated increases in flexibility after an acute bout of self-myofascial release (SMR) without any subsequent decreases in force output. Previous research has utilized measures of surface electromyography (sEMG) and mechanomyography (MMG) to examine the influence of SS on the electrical and mechanical processes of muscle activation, respectively. However, there is a lack of research examining the potential changes in electro-mechanical muscle activation post-SMR. PURPOSE: To examine the influence of SMR, via an acute bout of foam rolling (FR) to the vastus lateralis (VL), on the expression of knee extension force output and the inter-muscular electro-mechanical activation of the quadriceps musculature. STUDY DESIGN: Randomized crossover trial. METHODS: Twenty (10 males, 10 females) recreationally-active participants with prior FR experience completed both SMR and control (CON) testing protocols during separate testing sessions that were conducted in a randomized order 48 hours apart. During the SMR protocol, participants performed 3 sets of 60 seconds of FR over the VL portion of their quadriceps musculature, with 60 seconds of rest between sets. During the CON protocol, participants quietly sat upright for 10 minutes. Peak knee extension force output -(Forcepeak) data, as well as sEMG and MMG data from the VL and the rectus femoris (RF) were collected during maximal voluntary isometric contractions (MVICs) before and after both testing protocols. Root mean square sEMG and MMG amplitudes were calculated to represent electro-mechanical muscle activation of the VL (VL-sEMGRMS, VL-MMGRMS) and RF (RF-sEMGRMS, RF-MMGRMS) musculature. RESULTS: Repeated measures analyses of variance (RM ANOVAs) identified a significant (p < 0.05) increase in Forcepeak within the SMR protocol among males, but no change among females. No statistically significant changes in any electro-mechanical muscle activation measures were identified pre-to-post-SMR within either sex. CONCLUSION: In contrast to the SS literature body, these results suggest that SMR does not influence the electro-mechanical aspects of muscle activation during MVICs. These results provide support for the absence of decreases in force output post-SMR, but further examination regarding the potential muscle mass influence of SMR on electro-mechanical muscle function remains warranted. LEVEL OF EVIDENCE: 2c.

Contribution of the Autonomic Nervous System to Recovery in Firefighters.

CONTEXT: Sudden cardiac deaths (SCDs) have accounted for nearly half of the line-of-duty deaths among US firefighters over the past 10 years. In 2018, 33% of all SCDs occurred after the end of a fire service call. Researchers have suggested that an imbalance in autonomic nervous system (ANS) regulation of heart rate postcall may interfere with recovery in firefighters. OBJECTIVE: To use heart-rate recovery (HRR) and heart-rate variability (HRV), 2 noninvasive markers of ANS function, to examine the ANS recovery profiles of firefighters. DESIGN: Cross-sectional study. SETTING: Firehouse and research laboratory. PATIENTS OR OTHER PARTICIPANTS: Thirty-seven male career active-duty firefighters (age = 39 ± 9 years, height = 178.8 ± 5.4 cm, mass = 87.9 ± 11.2 kg). MAIN OUTCOME MEASURE(S): Percentage of maximal HR (%MHR) and HRV (natural log of the square root of the mean sum of the squared differences [lnRMSSD]) were collected after both submaximal and maximal exercise protocols during a 10-minute seated recovery. The HRR profiles were examined by calculating the asymptote, amplitude, and decay parameters of the monoexponential HRR curve for each participant. RESULTS: Differences in HRR parameters after 10 minutes of seated recovery were identified after submaximal versus maximal exercise (P < .001). In addition, although ANS was more suppressed after maximal exercise, HRV indicated incomplete recovery, and regardless of the test, recovery %MHR and lnRMSSD values did not return to pretest %MHR and lnRMSSD values. CONCLUSIONS: Our results suggest that the ANS contributions to recovery in active-duty firefighters are exercise-intensity specific, and this is likely an important factor when establishing best-practice recovery guidelines.

The effects of military style ruck marching on lower extremity loading and muscular, physiological and perceived exertion in ROTC cadets.

Military ruck marching with load carriage increases ground reaction forces, which are related to bone stress injuries (BSI). This study's purpose was to examine whether a ruck march increases impact loading and to describe muscular, physiological and perceived exertion in Army Reserve Officer Training Corps (ROTC) cadets. Secondary purposes examined relationships among loading changes after the ruck march and baseline characteristics. Fifteen Army ROTC cadets performed a 4-mile march. Lower extremity loading and muscular, physiological and perceived exertion were measured pre- and post-march. Results indicated significant increases in peak impact force and loading rate and decreases in ankle dorsiflexion and plantarflexion strength. Factors that might have been related to changes seen in lower extremity loading did not yield any compelling relationships to explain those changes. In conclusion, the ruck march led to increased peak impact force and loading rate, which have been shown to be related to the risk of BSI. Practitioner summary: This study examined ROTC cadets ankle strength and lower extremity loading before and after a ruck march. We found that lower extremity loading increased after the march, and ankle dorsiflexion (DF) strength decreased, despite the cadets not feeling fatigued. These changes are consistent with risk factors for bone stress injuries. Abbreviations: BSI: bone stress injury; ROTC: Reserve Officer Training Corps; PIF: peak impact force; LR: loading rate; RPE: rate of perceived exertion; APFT: Army physical fitness test; DF: dorsiflexors; PF: plantar-flexors; INV: invertors; EV: evertors; HHD: handheld dynamometer; %HRmax: percentage of maximum heart rate.

INTRA-RATER TEST-RETEST RELIABILITY AND RESPONSE STABILITY OF THE FUSIONETICS™ MOVEMENT EFFICIENCY TEST.

BACKGROUND: A new functional movement assessment, known as the Fusionetics- Movement Efficiency (ME) Test, has recently been introduced in the literature. Before the potential clinical utility of the ME Test can be examined, the reliability of this assessment must be established. PURPOSE: To examine the intra-rater test-retest reliability of the Fusionetics- ME Test. STUDY DESIGN: Cross-sectional. METHODS: ME Test data were collected among 23 (6 males, 17 females) university students (mean ± SD, age = 25.96 ± 3.16 yrs; height = 170.70 ± 9.96 cm; weight = 66.89 ± 12.67 kg) during sessions separated by 48 hours (Day 1, Day 2). All participants completed the seven sub-tests of the ME Test: 2-Leg Squat, 2-Leg Squat with Heel Lift, 1-Leg Squat, Push-Up, Shoulder Movements, Trunk Movements, and Cervical Movements. Overall ME Test scores and ME Test scores for each individual sub-test were calculated on a scale of 0 - 100 (worst - best) based on commonly observed movement compensations associated with each sub-test. RESULTS: Intraclass correlation coefficients (ICC3,1) statistics indicated that the intra-rater test-retest reliability of the Overall ME Test and individual sub-tests ranged from fair-to-excellent (ICC3,1 range = 0.55 - 0.84). Statistically significant differences in ME Test scores were identified between Day 1 and Day 2 among the 2-Leg Squat with Heel Lift (p = 0.015) and Cervical Movements (p = 0.005) sub-tests. In addition, a large range in the standard error of the measure (SEM) and minimal detectable change values (MDC90% & MDC95%) were identified within individual sub-tests of the ME Test (SEM range = 7.05 - 13.44; MDC90% range = 16.40 - 31.27; MDC95% range = 19.53 - 37.25), suggesting that the response stability varies among these individual sub-tests. Prevalence-adjusted bias-adjusted kappa statistics (κPABA) suggest that 55 of the 60 (92%) individual movement compensations hold moderate-to-almost perfect intra-rater test-retest reliability (κPABA range = 0.30 - 1.00). CONCLUSIONS: Excellent intra-rater test-retest reliability of the Overall ME Test score was identified, and thus, clinicians can reliably utilize the Fusionetics- ME Test to assess change in functional movement quality across time. However, caution should be taken if utilizing an individual sub-test to assess functional movement quality over time. LEVEL OF EVIDENCE: 2b.

Changes in Health and Fitness in Firefighter Recruits: An Observational Cohort Study.

PURPOSE: To observe longitudinal changes in health and fitness among firefighter recruits. METHODS: Body composition, aerobic capacity, muscular power, muscular strength, and muscular endurance measures were longitudinally collected among 27 male firefighter recruits (mean ± SD, age = 29.9 ± 4.1 yr; height, 179.8 ± 4.6 cm; body mass, 87.2 ± 9.7 kg) at the beginning (W1) and end (W14) of their firefighter training academy, as well as at the end of their probationary period (W38). RESULTS: Repeated-measures multivariate analyses of variance (RM MANOVA) identified significant changes across time among measures of body composition (F10,17 = 30.390, Λ = 0.053, P < 0.001), aerobic capacity (F6,21 = 55.111, Λ = 0.060, P < 0.001), muscular power (F8,17 = 2.785, Λ = 0.433, P = 0.036), muscular strength (F6,20 = 34.908, Λ = 0.087, P < 0.001), and muscular endurance (F4,23 = 25.983, Λ = 0.181, P < 0.001). Follow-up post hoc analyses indicated that all measures, except muscular power, significantly improved from W1 to W14 (P < 0.05). However, significant decrements in many of these measures were also observed from W14 to W38 (P < 0.05). CONCLUSIONS: The results of the current study suggest that measures of health and fitness among firefighter recruits significantly improved throughout the firefighter training academy (W1 to W14). However, many of these positive physiological adaptations are lost before these recruits finish their probationary period as active-duty firefighters (W14 to W38). These results highlight the importance of developing exercise programming that is designed for the active-duty firefighter cohort population to maintain the beneficial adaptations in health and fitness previously created during the firefighter training academy.

Resting Heart Rate Variability Among Professional Baseball Starting Pitchers.

Cornell, DJ, Paxson, JL, Caplinger, RA, Seligman, JR, Davis, NA, and Ebersole, KT. Resting heart rate variability among professional baseball starting pitchers. J Strength Cond Res 31(3): 575-581, 2017-The purpose of this study was to examine the changes in resting heart rate variability (HRV) across a 5-day pitching rotation schedule among professional baseball starting pitchers. The HRV data were collected daily among 8 Single-A level professional baseball starting pitchers (mean ± SD, age = 21.9 ± 1.3 years; height = 185.4 ± 3.6 cm; weight = 85.2 ± 7.5 kg) throughout the entire baseball season with the participant quietly lying supine for 10 minutes. The HRV was quantified by calculating the natural log of the square root of the mean sum of the squared differences (lnRMSSD) during the middle 5 minutes of each R-R series data file. A split-plot repeated-measures analysis of variance was used to examine the influence of pitching rotation day on resting lnRMSSD. A statistically significant main effect of rotation day was identified (F4,706 = 3.139, p = 0.029). Follow-up pairwise analyses indicated that resting lnRMSSD on day 2 was significantly (p ≤ 0.05) lower than all other rotation days. In addition, a statistically significant main effect of pitcher was also identified (F7,706 = 83.388, p < 0.001). These results suggest that professional baseball starting pitchers display altered autonomic nervous system function 1 day after completing a normally scheduled start, as day 2 resting HRV was significantly lower than all other rotation days. In addition, the season average resting lnRMSSD varied among participants, implying that single-subject analysis of resting measures of HRV may be more appropriate when monitoring cumulative workload among this cohort population of athletes.

In-Game Heart Rate Responses Among Professional Baseball Starting Pitchers.

Cornell, DJ, Paxson, JL, Caplinger, RA, Seligman, JR, Davis, NA, Flees, RJ, and Ebersole, KT. In-game heart rate responses among professional baseball starting pitchers. J Strength Cond Res 31(1): 24-29, 2017-The purpose of the current study was to characterize the in-game heart rate (HR) responses of baseball pitching. In-game HR was recorded from 16 professional baseball starting pitchers (mean ± SD, age = 22.1 ± 1.3 years; height = 187.9 ± 4.4 cm; weight = 90.5 ± 9.5 kg) for a total of 682 innings (home = 381, away = 301). All analyzed HR data were then normalized to each pitcher's age-predicted maximal HR (%HRmax). The group mean ± SD in-game %HRmax among all pitchers was 84.8 ± 3.9%, suggesting that baseball pitching is predominantly an anaerobic task. A split-plot mixed-model repeated measures analysis of variance identified a significant interaction effect between inning and game location (p = 0.042). Follow-up simple effects indicated that the in-game %HRmax was significantly different across innings, but only during home starts (p < 0.001). Specifically, pairwise analyses indicated that the in-game %HRmax during home starts were significantly (p ≤ 0.05) higher in the first and second innings than in all other innings. In addition, follow-up simple effects indicated that the in-game %HRmax was significantly (p = 0.017) higher during home starts than away starts in the first inning (87.3 ± 3.6% vs. 85.8 vs. 3.8%, respectively). Thus, it is possible that inning-dependent psychological factors may have contributed to the observed changes in in-game physiological intensity across innings and that these factors are specific to game location. Consequently, strength and conditioning practitioners should prescribe high-intensity exercises when developing conditioning programs for professional baseball starting pitchers.

Measures of health, fitness, and functional movement among firefighter recruits.

AIM: The purpose of this study was to examine the associations between various health and fitness measures and Functional Movement Screen™ (FMS™) scores among 78 firefighter recruits. METHODS: Relationships between FMS™ scores and age, body mass index (BMI), sit and reach (S&R) distance, estimated maximal aerobic capacity (V˙O2max), estimated one-repetition maximum squat (1RM-Squatmax), and plank endurance (%Plankmax) were examined. RESULTS: Total FMS™ scores were significantly correlated with BMI (r = -0.231, p = 0.042), estimated 1RM-Squatmax (r = 0.302, p = 0.007), and %Plankmax (r = 0.320, p = 0.004). Multiple regression analyses indicated that this combination of predictors significantly predicted (F(3, 74) = 5.043, p = 0.003) Total FMS™ score outcomes and accounted for 17% of the total variance (R2 = 0.170). In addition, logistic regression analyses indicated that estimated 1RM-Squatmax also significantly predicted (χ2 = 6.662, df = 1, p = 0.010) FMS™ group membership (≤14 or ≥15). CONCLUSION: These results suggest that the health and fitness measures of obesity (BMI), bilateral lower extremity strength (estimated 1RM-Squatmax), and core muscular endurance (%Plankmax) are significantly associated with functional movement patterns among firefighter recruits. Consequently, injury prevention programs implemented among firefighter recruits should target these aspects of health and fitness.

Influence of body mass index on movement efficiency among firefighter recruits.

BACKGROUND: Previous research has demonstrated links between musculoskeletal injury risk and measures of obesity and movement efficiency among the firefighter population. However, the influence of obesity on movement efficiency among firefighter recruits remains uninvestigated. OBJECTIVE: To investigate the influence of obesity on movement efficiency measures among firefighter recruits. METHODS: Measures of obesity were collected among 73 male firefighter recruits. Participants were grouped into standard body mass index (BMI) categories (normal, overweight, obese). Differences in Total Functional Movement Screen (FMS) scores and Y-Balance Test (YBT) composite scores were examined between BMI categories. In addition, the relationships between measures of obesity and movement efficiency were also examined. RESULTS: No significant differences in movement efficiency measures were identified between BMI categories (p > 0.05). However, significant bivariate correlations were identified between BMI (kg/m2) and Total FMS score (r = -0.235, p = 0.045), as well as between fat-free mass (FFM) and Total FMS score (r = -0.231, p = 0.049), when examined among all participants. CONCLUSIONS: BMI may influence measures of movement efficiency among firefighter recruits to a lesser extent than among other previously examined populations. Future research should examine the influence of other unexamined physiological variables on movement efficiency.

The effects of fatigue and anticipation on the mechanics of the knee during cutting in female athletes.

BACKGROUND: Unanticipated cutting tasks which do not allow for pre-planning of a movement have been reported to promote knee mechanics which may increase the risk of anterior cruciate ligament injury. Fatigue has also been reported to have similar effects. Athletes must often perform unanticipated tasks when they are fatigued. Previous studies have reported that the effects of anticipation become more prominent as an athlete progresses through a fatigue protocol. However, the protocols previously utilized may not mimic the demands of sports participation. METHODS: Three-dimensional knee joint kinematics and kinetics were collected from 13 female athletes while they performed a run-and-cut task, before and after completion of an intermittent shuttle run. Trials were further divided (pre-planned, unanticipated) to assess the effects of anticipation. FINDINGS: There were no significant interactions between the effects of fatigue and anticipation for the peak knee angles or moments of the knee joint in any plane. Subjects did demonstrate a 68% increase in their peak knee abduction angles following completion of the intermittent shuttle run. Anticipation also had a significant effect on the mechanics of the knee in all planes. Most notably, there was a 23% increase in peak knee abduction angles and a 33% increase in the peak internal knee adduction moments. INTERPRETATION: Both fatigue and anticipation promoted knee mechanics which are associated with an increased risk of knee injury. However, it does not appear that their effects combine when athletes are at a level of fatigue which is thought to reflect sports participation.