Helmetless Tackling Training Intervention and Preseason Self-efficacy Effects on Head Impacts in Hawai'i High School Football.

OBJECTIVE: To determine how football head impacts are influenced by self-efficacy (SE), helmetless tackling intervention participation (IP), and years of experience (YE) playing football. DESIGN: Cross-sectional. SETTING: Three high schools. PARTICIPANTS: 120 (male; n = 118, female; n = 2, 15.57 ± 1.23 years) participants were recruited from 5 high school teams (3 varsity and 2 junior-varsity). INDEPENDENT VARIABLES: SE, days of IP, and YE playing tackle football. MAIN OUTCOME MEASURES: SE was measured using a 53-question survey and categorized into 5 subscales. The accumulation of total head impacts (THI) was measured using Riddell InSite Speedflex helmets (Elyria, OH) throughout the season. Head impact exposure (HIE) was standardized as a ratio of impacts per session (games, scrimmages, and practices). Multiple regression analyses tested the relationship between THI or HIE with the predictor variables. RESULTS: For THI, 22.1% was explained by the predictors (r = 0.470, r2 = 0.221). Intervention participation had a negative correlation (B = -4.480, P = 0.019), whereas confidence in performing proper tackling and blocking (SE1) (B = 3.133, P = 0.010) and >8 YE (B = 135.9, P = 0.009) positively correlated with THI. For HIE, 25.4% was explained by the predictors (r = 0.504, r2 = 0.254). Intervention participation negatively correlated (B = -0.077, P = 0.007), whereas SE1 (B = 3.133, P = 0.010) and >8 YE (B = 2.735, P ≤ 0.001) correlated positively with HIE. CONCLUSIONS: Increased head impacts were associated with less helmetless tackling participation, more than 8 YE, and more self-confidence in tackling ability. Increasing the amount of time athletes spend practicing proper tackling and blocking techniques to reduce head first and risky play is warranted to reduce the amount of head impacts received over time.

TEST-RETEST RELIABILITY AND RELIABLE CHANGE INDEX OF MOBILE APPLICATION NEUROCOGNITIVE TEST AMONG MIDDLE AND HIGH SCHOOL ATHLETES.

CONTEXT: A mobile application neurocognitive assessment has been used in place of equipment intensive computerized neurocognitive assessment protocol. A previous study reported high to very high test-retest reliability of neurocognitive assessment using the mobile application in healthy adults, but no studies have examined test-retest reliability, reliable change indices (RCIs), and sex effect in middle school and high school populations when conducted 1 year apart. OBJECTIVE: The purpose of this study was to examine the test-retest reliability and RCIs of baseline data collected at 2-time points approximately 1 year apart using a mobile application neurocognitive rest in middle school and high school athletes. The secondary purpose of the study was to investigate the sex difference in neurocognitive measures. DESIGN: Cross-sectional study. SETTING: Institutional. PATIENTS OR OTHER PARTICIPANTS: 172 middle school and high school healthy student-athletes (mean age=13.78±1.59 years old). MAIN OUTCOME MEASURE(S): Mobile application neurocognitive rest scores (reaction time, impulse control, inspection, and memory). RESULTS: The result from the study demonstrated that neurocognitive measures had low test-retest reliability across a 1-year time period in middle and high school settings. Upon retesting, reaction time and inspection time improved significantly in both middle and high school athletes, and impulse control showed significant improvement in middle school athletes. More athletes in middle school showed more RCI improvements compared to high school athletes. While both males and females demonstrated improvements in neurocognitive measures throughout adolescence, males outperformed females on reaction time and impulse control. CONCLUSIONS: Findings from the study indicate unacceptably low test-retest reliability of a mobile application neurocognitive test most likely due to cognitive development occurring throughout adolescence. Additionally, significant RCIs were noted. These naturally occurring improvements due to cognitive development could mask the post-concussion deficits. The findings warrant consideration of age and sex on the neurocognitive performance of middle and high school athletes.

Odor descriptive ratings can predict some odor-color associations in different color features of hue or lightness.

Background: Olfactory information can be associated with color information. Researchers have investigated the role of descriptive ratings of odors on odor-color associations. Research into these associations should also focus on the differences in odor types. We aimed to identify the odor descriptive ratings that can predict odor-color corresponding formation, and predict features of the associated colors from the ratings taking into consideration the differences in the odor types. Methods: We assessed 13 types of odors and their associated colors in participants with a Japanese cultural background. The associated colors from odors in the CIE L*a*b* space were subjectively evaluated to prevent the priming effect from selecting color patches. We analyzed the data using Bayesian multilevel modeling, which included the random effects of each odor, for investigating the effect of descriptive ratings on associated colors. We investigated the effects of five descriptive ratings, namely Edibility, Arousal, Familiarity, Pleasantness, and Strength on the associated colors. Results: The Bayesian multilevel model indicated that the odor description of Edibility was related to the reddish hues of associated colors in three odors. Edibility was related to the yellow hues of colors in the remaining five odors. The Arousal description was related to the yellowish hues in two odors. The Strength of the tested odors was generally related to the color lightness. The present analysis could contribute in investigating the influence of the olfactory descriptive rating that anticipates the associated color for each odor.

Physiological comfort evaluation under different airflow directions in a heating environment.

BACKGROUND: Indoor airflow and thermal comfort are difficult to assess through subjective evaluations because airflow sensations can differ based on various factors, such as personal characteristics, interests, preferences, and the current state of mind. Thus, subjective evaluations should be combined with objective assessments, such as physiological measurements. This study evaluated airflow and thermal comfort through physiological measurements, including skin temperature, electroencephalography, respiration, and electrocardiography, in addition to subjective evaluations. METHODS: Twenty participants entered a test room at 30 °C after staying in an acclimation room at 18 °C for 20 min. They were exposed to indirect and direct airflow toward their faces and performed four tasks under each condition: resting, counting to 10 s following time alerts, counting to 10 s in the mind, and mental calculation. The mean speed of the air directed to the participants' faces was 0.123 m/s and 0.225 m/s in the indirect and direct conditions, respectively. RESULTS: The gamma and beta bands of electroencephalograms taken at the left-temporal (T3) and left-parietal (P7) sites showed significantly lower amplitudes under the indirect condition (gamma, T3: p = 0.034, P7: p = 0.030; beta, T3: p = 0.051, P7: p = 0.028). Similarly, the variability of respiration was lower under the indirect condition (p < 0.010). The amplitudes of gamma and beta waves showed significant correlations with anxiousness levels (gamma, T3: r = 0.41; beta, T3: r = 0.35). CONCLUSIONS: Our results suggest that indirect heating airflow causes lower mental stress and fatigue than those induced by direct flow, which is equivalent to more comfort. The results of this study suggest that physiological measurements can be used for the evaluation of unconscious indoor comfort, which cannot be detected by subjective evaluations alone.

Neurofeedback training improves episodic and semantic long-term memory performance.

Understanding and improving memory are vital to enhance human life. Theta rhythm is associated with memory consolidation and coding, but the trainability and effects on long-term memory of theta rhythm are unknown. This study investigated the ability to improve long-term memory using a neurofeedback (NFB) technique reflecting the theta/low-beta power ratio on an electroencephalogram (EEG). Our study consisted of three stages. First, the long-term memory of participants was measured. In the second stage, the participants in the NFB group received 3 days of theta/low-beta NFB training. In the third stage, the long-term memory was measured again. The NFB group had better episodic and semantic long-term memory than the control group and significant differences in brain activity between episodic and semantic memory during the recall tests were revealed. These findings suggest that it is possible to improve episodic and semantic long-term memory abilities through theta/low-beta NFB training.

Physiological and subjective comfort evaluation under different airflow directions in a cooling environment.

Indoor comfort is influenced by airflow direction, but subjective evaluations can differ. This study evaluates the airflow comfort with subjective assessments and physiological measurements, including skin temperature, electroencephalograms, and electrocardiograms. Nineteen participants entered a test room at 20°C after staying in a room at 32°C for acclimation. They were exposed to indirect and direct airflow conditions to their faces and performed four tasks under each condition: resting, counting to 10 s following time alerts, counting to 10 s in mind, and mental calculation. Subjective assessments showed relatively higher thermal sensation and pleasantness under indirect airflow. The psychological time calculated from counting behaviors was longer under indirect airflow, indicating suppression of negative emotions. The face temperatures significantly declined during experiments under direct airflow. The beta and gamma bands of electroencephalograms were inhibited under the indirect condition, and these amplitudes were negatively correlated with pleasant feelings. Electrocardiogram parameters indicated that sympathetic nervous activity was predominant during counting, following alerts and mental calculation in indirect airflow. This study supports the comfort of indirect airflow based on reliable evidence.

The effect of Kinesio-tape® on pain and vertical jump performance in active individuals with patellar tendinopathy.

BACKGROUND: Patellar tendinopathy is a common inflammatory condition in athletes who undergo large volumes of running and jumping. Kinesio-tape® (KT) is proposed to provide pain relief; however, its effect has not been examined on patellar tendinopathy. OBJECTIVE: To examine the effects of KT on pain modulation for active individuals with patellar tendinopathy during functional activities. METHODS: Thirteen symptomatic knees from seven college-aged females (6 bilateral; 1 unilateral) were included. Participants underwent three data collection sessions with KT, sham, and no tape (NT) in a randomized order. During the session, participants performed a maximum vertical jump, single-leg squats and isometric knee extension. The KT intervention was applied according to the KT manual and the sham utilized the same pattern without tension. Pain level was evaluated using the numeric pain scale before, during and after each activity. Function was assessed as maximum vertical jump height and maximum isometric strength. A separate repeated measures ANOVA was used to compare each dependent variable (pain level, vertical jump height, and isometric strength) among the conditions. RESULTS: Reported pain scores were significantly lower (p = 0.05) during the maximal vertical jump test for KT (3.38 ± 1.26) compared to NT (4.54 ± 2.22). Significantly lower jump heights were found under KT (17.73 ± 3.06in) during the maximum vertical jump test compared to sham (18.65 ± 2.17in, p = 0.000) and NT (18.18 ± 2.93in, p = 0.008). CONCLUSIONS: The use of the KT tape with a tendon corrective strip and muscle facilitative strip was effective for decreasing pain associated with patellar tendinopathy during jump landing but led to decreased maximum jump height. CLINICAL TRIAL IDENTIFIER: NCT04153877.

Concussion Recovery Timeline of High School Athletes Using A Stepwise Return-to-Play Protocol: Age and Sex Effects.

CONTEXT: Implementation of a stepwise return-to-play (RTP) protocol has become the standard management strategy for high school athletes to ensure a safe RTP after concussion. The detailed characteristics of the recovery timeline throughout the steps of an RTP protocol have not been delineated among the adolescent population. OBJECTIVE: To investigate the days spent in each step of the stepwise RTP protocol in an adolescent population and examine the effects of age and sex on recovery time. DESIGN: Cross-sectional study. SETTING: Local schools. PATIENTS OR OTHER PARTICIPANTS: Student-athletes from 57 schools. INTERVENTION(S): A total of 726 patients with concussion (age = 15.5 ± 1.2 years, males = 454, females = 272) were included. The 7-step RTP protocol consists of the following steps: (1) complete cognitive rest, (2) full return to school, (3) light exercise, (4) running progression, (5) noncontact training drills and weight training, (6) full-contact practice or training, and (7) return to game play. The data were obtained by certified athletic trainers as a part of the statewide standardized concussion-management protocol. MAIN OUTCOME MEASURE(S): Days spent in steps 0 to 6 as well as a breakdown of days by sex and age. RESULTS: The average total RTP days were 20.2 ± 13.9. Half of this time was spent in the return-to-school phase (steps 2-3: 10.2 ± 10.0 days). Compared with 17-year-old participants, younger participants (age = 14-16 years) took 3 or 4 days longer to start step 3 and to reach step 6 (P < .05). Females took longer to reach step 6 than males (21.6 ± 15.5 versus 19.3 ± 12.7 days) because they took longer to reach step 3 (14.7 ± 11.4 days) than males (13.0 ± 10.0 days; P < .05). CONCLUSIONS: Our study provides an estimated stepwise concussion recovery timeline for adolescent student-athletes. Clearance to start step 3 was the benchmark for the recovery timeline, as the duration of the exercise portion of the protocol was consistent across the age and sex groups.

MRI-based visualization of rTMS-induced cortical plasticity in the primary motor cortex.

Repetitive transcranial magnetic stimulation (rTMS) induces changes in cortical excitability for minutes to hours after the end of intervention. However, it has not been precisely determined to what extent cortical plasticity prevails spatially in the cortex. Recent studies have shown that rTMS induces changes in "interhemispheric" functional connectivity, the resting-state functional connectivity between the stimulated region and the symmetrically corresponding region in the contralateral hemisphere. In the present study, quadripulse stimulation (QPS) was applied to the index finger representation in the left primary motor cortex (M1), while the position of the stimulation coil was constantly monitored by an online navigator. After QPS application, resting-state functional magnetic resonance imaging was performed, and the interhemispheric functional connectivity was compared with that before QPS. A cluster of connectivity changes was observed in the stimulated region in the central sulcus. The cluster was spatially extended approximately 10 mm from the center [half width at half maximum (HWHM): approximately 3 mm] and was extended approximately 20 mm long in depth (HWHM: approximately 7 mm). A localizer scan of the index finger motion confirmed that the cluster of interhemispheric connectivity changes overlapped spatially with the activation related to the index finger motion. These results indicate that cortical plasticity in M1 induced by rTMS was relatively restricted in space and suggest that rTMS can reveal functional dissociation associated with adjacent small areas by inducing neural plasticity in restricted cortical regions.

Olfactory modulation of colour working memory: How does citrus-like smell influence the memory of orange colour?

Olfactory modulation of vision is not well understood whereas visual modulation of olfaction has been more fully investigated. This study aimed to reveal in a simple manner whether there is olfactory modulation of colour working memory using an odour that induces a citrus-like smell and is associated with orange colours. We assumed that the odour would have modulatory effects on the colour information stored in working memory. To clarify whether these effects are supportive or disruptive, during the colour working memory task we measured an event-related potential component, P3, which is involved in attentional processes of working memory. The results indicated that odour presentation mediated a decline in the rate of correct guesses for orange colours. Furthermore, the odour suppressed P3 during reddish-colour retrieval, including orange. These results suggest that colour working memory in orange can be disrupted via olfactory modulation with citrus-like odours.

The Face ­ A Vascular Perspective. A literature review

Vascular supply is key for maintenance of healthy tissue conditions but also with regard to healing following trauma or therapeutic interventions. The face is probably the most exposed part of the body and any changes of vascularity are readily visible (skin blanching, ecchymosis, hematoma, edema). With regard to the arterial supply, all vessels reaching the facial skin originate from the bilateral common carotid arteries. The ophthal­mic artery is considered the major arterial shunt between the internal and external carotid artery systems. Main arterial contributors to the face include the facial, transverse facial, and infraorbital arteries. In general, homonymous veins accompany the arteries, but there are some exceptions (inferior ophthalmic vein, retromandibular vein). Furthermore, the facial vein demonstrates a consistently more posterior course compared to the facial artery. Lymphatic vessels including lymph nodes play an important role for facial drainage.

Reliability of clinically feasible dual-task tests: Expanded timed get up and go test as a motor task on young healthy individuals.

Dual-Task testing has been reported to have a higher sensitivity to deficits associated with concussion; however, the feasibility as a clinical or field test is questionable due to the requirements of laboratory-based equipment. With an overarching goal of exploration of clinically feasible Dual-Task testing options, the specific aims of this study were 1) to evaluate the reliability of Dual-Task testing methods using the Expanded Timed Get-Up-and-Go (ETGUG) paired with Backward Digit Recall (BDR), Serial Seven (SS), and Auditory Pure Switch Task (APST), and 2) to determine the effects of Dual-Task testing on motor and cognitive performance in healthy college-aged individuals. Fifty-four healthy young adults completed two separate testing sessions, which consisted of Single-Task tests in a randomized order followed by 3 pairs of Dual-Task tests in a randomized order. Test-retest reliability for ETGUG time to completion was excellent for all Single- and Dual-Task conditions (ICC 0.89-0.92); however, ETGUGBDR and ETGUGSS were associated with learning effects (p=0.002 and 0.007, respectively). Test-retest reliability for Response Rate of the cognitive tasks was lower than those of motor task and all outcomes were associated with learning effects. The completion time of the ETGUGAPST pair indicated excellent reliability with no learning effect. Performance level declined in all tasks under Dual-Task conditions compared to Single-Task; however, motor tasks showed larger deficits indicating the prioritization of the cognitive task compared to the motor task.

Physiological activity in calm thermal indoor environments.

Indoor environmental comfort has previously been quantified based on the subjective assessment of thermal physical parameters, such as temperature, humidity, and airflow velocity. However, the relationship of these parameters to brain activity remains poorly understood. The objective of this study was to determine the effect of airflow on brain activity using electroencephalograms (EEG) of participants in a living environment under different airflow conditions. Before the recording, the room was set to a standardised air temperature and humidity. During the recording, each participant was required to perform a simple time-perception task that involved pressing buttons after estimating a 10-second interval. Cooling and heating experiments were conducted in summer and winter, respectively. A frequency analysis of the EEGs revealed that gamma and beta activities showed lower amplitudes under conditions without airflow than with airflow, regardless of the season (i.e., cooling or heating). Our results reveal new neurophysiological markers of the response to airflow sensation. Further, based on the literature linking gamma and beta waves to less anxious states in calm environments, we suggest that airflow may alter the feelings of the participants.

The effects of ankle braces and taping on lower extremity running kinematics and energy expenditure in healthy, non-injured adults.

Ankle braces and taping are commonly used to prevent ankle sprains and allow return to play following injury, however, it is unclear how passive restriction of joint motion may effect running gait kinematics and energy expenditure during exercise. The purpose of this study was to determine the effect of different types of ankle supports on lower extremity kinematics and energy expenditure during continuous running. Thirteen healthy physically active adults ran at self-selected speed on the treadmill for 30min in four different ankle support conditions: semi-rigid hinged brace, lace-up brace, tape and control. Three-dimensional lower extremity kinematics and energy expenditure were recorded every five minutes. The semi-rigid hinged brace was most effective in restricting frontal plane ankle motion. The lace-up brace and tape restricted sagittal plane ankle motion, while semi-rigid hinged bracing allowed for normal sagittal plane ankle kinematics. Kinematic changes from all three ankle supports were generally persistent through 25-30min of exercise. Only tape influenced knee kinematics, limiting flexion velocity and flexion-extension excursion. Small but significant increased in energy expenditure was found in tape and semi-rigid hinged brace conditions; however, the increases were not to any practically significant level (<0.5kcal/min).

Evaluation of Cognitive Function When Hearing One's Own Name in Patients With Brain Injuries in Early Developmental Stages.

PURPOSE: The level of residual cognitive function in patients with early brain injury is a key factor limiting rehabilitation and the quality of life. Although understanding residual function is necessary for appropriate rehabilitation, the extent of its effects on cognitive improvement remains unknown. This study evaluated cognitive function in patients with severe motor and intellectual disabilities after early brain injuries due to cerebral hemorrhage or periventricular leukomalacia. We focused on neural responses to hearing the subject's own name (SON). According to previous studies, differences in response to SON are associated with several types of cognitive dysfunction. METHODS: We examined healthy subjects (aged 21.4 ± 1.10 years; control) and patients with a previous brain injury (aged 13-27 years at the time of our analysis) resulting in periventricular leukomalacia or a cerebral hemorrhage during the perinatal period or childhood. We recorded EEG responses to the SON and to other Japanese words, obtaining EEG-evoked potentials with wavelet transformations. RESULTS: Compared with healthy controls, beta power (not alpha power) revealed differences in response to SON by patients with brain injury, especially those with cerebral hemorrhage. CONCLUSIONS: We suggest that alpha and beta power differences reflect different cognitive functions and that the SON response reveals more than one process. Beta powers may reflect the intellectual disability of cognitive function in response to self-relevant stimuli, especially in patients with cerebral hemorrhage. Meanwhile, alpha powers did not differ from those of the healthy controls, suggesting that the patients perhaps paid attention to their own names.

Asymmetry between lower limbs during rested and fatigued state running gait in healthy individuals.

Although normal gait is often considered symmetrical in healthy populations, differences between limbs during walking suggest that limbs may be used preferentially for braking or propulsion. The purpose of this study was to evaluate kinematic and kinetic variables, at both rested state and following a two-stage treadmill fatiguing run, for asymmetry between limbs. Kinematic (240Hz) and kinetic (960Hz) running data were collected bilaterally for 20 physically active individuals at both rested and fatigued states. Symmetry angles were calculated to quantify asymmetry magnitude at rested and fatigued states. Paired t-tests were used to evaluate differences between right and left limbs at rested and fatigued states, as well as rested and fatigued states symmetry angles. Variables that have been previously associated with the development of overuse injuries, such as knee internal rotation, knee stiffness, loading rate, and adduction free moment, were found to be significantly different between limbs at both rested and fatigued states. Significant differences in vertical stiffness were found, potentially indicating functional asymmetry during running. Symmetry angle was used to investigate changes in percentage of asymmetry at rested and fatigued states. Small (1-6%), but significant decreases in vertical stiffness, loading rate, and free moment symmetry angles indicate that these variables may become more symmetrical with fatigue. Knee internal rotation and knee stiffness became more asymmetrical with fatigue, increasing by 14% and 5.3%, respectively. The findings of the current study indicate that fatigue induced changes in gait may progress knee movement pattern asymmetry.

Hearing subject's own name induces the late positive component of event-related potential and beta power suppression.

The neuronal response to hearing a subject's own name (SON) has been often investigated using event-related potential (ERP) or time-frequency analysis, but seldom by a combination of these methods. Using this combination of approaches would allow the relationship between memory processes engaged by SON and the neuronal responses to be studied in more detail. Thus, the present study used both ERP and time-frequency analysis to investigate memory process for SON by comparing the responses to SON and to unfamiliar names. Specifically, the SON condition was compared with two control conditions: repeated unfamiliar names and singly presented unfamiliar names. This experimental design allowed us to determine the differences in memory processes between hearing one's own name and hearing unrelated but repeatedly heard names. ERP analysis showed that SON elicited a late positive component in parietal areas, while unfamiliar names elicited no positivity. Beta power suppression was observed in response to SON at 0.4-0.6s after stimulus onset at right central sites, but not in response to unfamiliar names. These results are indicative of an involvement of episodic memory processes on hearing SON, which corresponds to the recognition of one's own name. Further, the ERP results suggest the presence of a "new" stimulus recognition process that is activated by singly presented unfamiliar names but not by repeated unfamiliar names.

Lethal male combats in Schizotetranychus brevisetosus (Acari: Tetranychidae) on blue Japanese oak (Quercus glauca).

Male spider mites (Acari: Tetranychidae) guard preimaginal quiescent females to reserve paternity. In a few species of Stigmaeopsis that make densely woven silky nests on the surface of host plants, mature males attack and even kill rivals to gain their rights to inseminate young females in the nest. Here we report that the adult males of Schizotetranychus brevisetosus (Acari: Tetranychidae), whose web nest construction behavior evolved independently from Stigmaeopsis spp., also exhibit highly aggressive behavior towards one another. Combat mortality was measured in an experimental design where two males in the treatment group were forced to live in a nest made by adult females on a leaf arena, while one male in the control group was allowed to live in a nest on another arena. We found that the 5-day mortality of males in the treatment group (56 and 37 % in two replicates) was significantly higher than in the control group (9 and 12 %) and that lethal combats frequently arose in the treatment group. However, we found no consistent trend for the length of the first legs, which is known to affect the outcome of battle in Tetranychus urticae and Stigmaeopsis miscanthi. This might be due to a relatively small number of measurable specimens, and the effects of body size should be explored in future studies.

Phase-locked theta activity evoked in patients with severe motor and intellectual disabilities upon hearing own names.

BACKGROUND: Severe motor and intellectual disability (SMID) patients cannot express their feelings with language. Understanding what they are thinking about or how they feel is thus difficult. This study focused on brain responses to hearing their own names to clarify the situation in these patients. METHODS: We performed and analyzed electroencephalography (EEG) for six patients with SMID and eleven healthy subjects. All subjects were presented with auditory stimuli including calling the subject's own name (SON) and reading words. EEG was analyzed by time-frequency analysis, event-related spectral perturbation (ERSP) to detect EEG power changes caused by EEG amplitude, and inter-trial coherence (ITC) to investigate phase-locked changes. RESULTS: ERSP results from healthy subjects showed significant theta power increases as a specific response to SON. While we could not identify a similar pattern in the responses of patients with SMID, analysis of ITC revealed that theta phase-locked activity increased in response to SON not only in all healthy subjects, but also in four patients. DISCUSSION: These results indicate that theta phase-locked activity in some patients with SMID was strongly associated with SON, as in healthy subjects. Our study suggests the existence of specific neural markers that signal an attentional shift in patients upon hearing SON.

Allometric scaling of strength scores in NCAA division I-A football athletes.

This study examined population-specific allometric exponents to control for the effect of body mass (BM) on bench press, clean, and squat strength measures among Division I-A collegiate football athletes. One repetition maximum data were obtained from a university pre-season football strength assessment (bench press, n = 207; clean, n = 88; and squat n = 86) and categorized into 3 groups by positions (line, linebacker, and skill). Regression diagnostics and correlations of scaled strength data to BM were used to assess the efficacy of the allometric scaling model and contrasted with that of ratio scaling and theoretically based allometric exponents of 0.67 and 0.33. The log-linear regression models yielded the following exponents (b): b = 0.559, 0.287, and 0.496 for bench press, clean, and squat, respectively. Correlations between bench press, clean, and squat to BM were r = -0.024, -0.047, and -0.018, respectively, suggesting that the derived allometric exponents were effective in partialling out the effect of BM on these lifts and removing between-group differences. Conversely, unscaled, ratio-scaled, and allometrically scaled (b = 0.67 or 0.33) data resulted in significant differences between groups. It is suggested that the exponents derived in the present study be used for allometrically scaling strength measures in National Collegiate Athletic Association Division I-A football athletes. Use of the normative percentile rank scores provide coaches and trainers with a valid means of judging the effectiveness of their training programs by allowing comparisons between individuals without the confounding influence of BM.