M.S. - Kinesiology and Rehabilitation Science

Permanent URI for this collectionhttps://hdl.handle.net/10125/36915

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Subjective readiness in American football: Evaluating the effects of travel on player readiness
(University of Hawai'i at Manoa, 2025) Blanchette, Grace; Yamada, Paulette; Kinesiology and Rehabilitation Science
This study examined the impact of travel on perceived readiness in NCAA Division I American football players, utilizing the Hooper Index and practice load across home and away conditions. Results revealed that athletes reported better sleep quality, lower fatigue, and reduced DOMS when traveling, despite higher perceived practice loads during away games, suggesting that structured travel routines may enhance perceptual readiness contrary to prior assumptions. These findings highlight the potential benefits of travel logistics in supporting athlete preparation, particularly as collegiate conference realignment increases travel demands, though elevated away-game practice loads underscore the need to manage competitive strain.
The influence of injury status on neuromuscular status monitoring in collegiate beach volleyball athletes
(University of Hawai'i at Manoa, 2025) Gangle, Hailie Meeshel; Yamada, Paulette; Kinesiology and Rehabilitation Science
Background: Neuromuscular status monitoring is critical for roster availability and performance optimization in collegiate athletes. Purpose: This study aimed to examine the relationship between neuromuscular fatigue indicators, as measured by countermovement jump force plate testing, and injury occurrence in Division I collegiate beach volleyball student-athletes. Methods: Twenty-one female collegiate beach volleyball athletes were followed throughout the 2023-2024 competitive season. Weekly countermovement jump tests were conducted to assess neuromuscular status, and athletes were flagged for neuromuscular fatigue if jump height (flight time) was lower than one coefficient of variation from their baseline mean. Countermovement depth during countermovement jump was measured. Injury data was concurrently collected via electronic medical records and athlete participation status was categorized as "out," "limited," or "as tolerated.” The primary outcomes were the percent of flagged athletes concurrently listed on the injury report. Results: A total of 63 injuries were recorded throughout the 2024 competitive season. Athletes flagged for movement-based metrics (e.g., flight time/contraction time (RSImod) and countermovement depth) demonstrated the strongest association with injury, with 25.0% of RSI mod flags coinciding with an injury. Comparatively, jump height was flagged in 29.0% of instances, but only 20.6% were injury-related, suggesting movement-based metrics may be more indicative of injury status than output-based measures. Conclusion: The findings highlight the need for integrated athlete monitoring, suggesting that movement based metrics (RSImod and countermovement depth) are sensitive indicators of neuromuscular dysfunction associated with injury. Collaborative data interpretation between sports medicine and strength and conditioning personnel is essential to reduce misclassification and enhance roster availability strategies.
THE EFFECT OF ACL RECONSTRUCTION ON TOTAL JOINT WORK AND JOINT WORK CONTRIBUTIONS
(University of Hawai'i at Manoa, 2024) Tanuvasa, Eliki; Stickley, Christopher; Kinesiology and Rehabilitation Science
Context: Increased long-term risk of developing knee osteoarthritis (OA) following anteriorcruciate ligament reconstruction (ACLR) is widely established. Mechanical loading plays a significant role in keeping articular cartilage healthy. Examining the mechanical joint work in joints or legs offers the potential to provide a fuller understanding of overall knee loading because it encompasses exposure to both positive and negative power throughout the entire stance phase. Persistent compensatory underloading of the knee during running may play a critical role in driving cellular and metabolic changes associated with the progression of knee OA. Therefore, the purpose of this study was to examine differences in sagittal plane joint work during running between ACLR (ACL) and healthy control (MATCHED) subjects at least two years after unilateral ACLR. Methods: Running biomechanics of 37 ACLR (27.0 ± 6.6yr, 1.7 ± 0.1m, 75.6 ± 21.1kg; 23 females; 8.3 ± 5.3 years post-ACLR) and 37 healthy control subjects (24.6 ± 4.7yr, 1.7 ± 0.1m, 73.0 ± 20.1kg; 23 females) were evaluated. Current activity levels were evaluated with the Tegner Activity Scale (5.84 ± 1.4 ACLR, 5.73 ± 1.6 CON). Subjects performed trials running at a velocity of 4.0 m/s-1 ± 10%. The ACLR limb was individually matched to CON via limb dominance. Kinematics were collected at 240Hz via 3D motion capture system (Vicon, Colorado, USA); kinetics were collected at 960Hz using a force plate (AMTI, Massachusetts, USA). Kinematic and kinetic data were smoothed using a Butterworth filter with a 10Hz cut-off frequency, except for ground reaction force which was filtered at 50 Hz, and processed using Visual 3D (C-Motion, Inc., Germantown, MD). T-tests were used to determine differences in gait-related variables during stance between ACLR vs their contralateral limb (CONTRA) and vs CON matched limbs. Sagittal plane work was calculated by taking the integral of the pow\]er curve during stance via the trapezoidal rule. Total joint work was 1 calculated as the absolute value of positive and negative work. Total leg work was calculated as the sum of hip, knee, and ankle work while the percentage of total joint work to total leg work represented the joint work contribution. Results: Total negative knee work and total knee work were significantly (P<0.05) lower in the ACLR limb than in the matched CON limb. The largest differences were demonstrated between ACLR and CONTRA limbs which included total negative knee work, total positive knee work, total knee work, total leg work, knee work contribution, and ankle work contribution (Table 1). Conclusions: ACLR limbs with an average of 8 years post-surgery demonstrated lower knee joint work loading during running than their CONTRA limb and matched CON limbs. Consequently, ACLR limbs demonstrated a compensatory pattern of increasing the percentage of ankle work contribution in response to the reduced knee joint work contribution. Similar reports of long-term abnormal underloading of discrete gait variables following ACLR have been associated with cartilage thinning and degeneration. Joint work may provide a more comprehensive representation of loading exposure and volume over stance. These chronic underloading patterns of the knee during gait may influence long-term cartilage degeneration and increased risks of developing OA within 10-20 years after ACLR.
STROBOSCOPIC VISUAL DISRUPTION EFFECTS ON RUNNING BIOMECHANICS BETWEEN POST-OPERATIVE ACLR PATIENTS AND HEALTHY CONTROLS
(University of Hawai'i at Manoa, 2024) Merrill, Alexis; Stickley, Christopher; Kinesiology and Rehabilitation Science
Objective: To examine the extent to which the use of SVFD elicits differences in somatosensory function during loading while running between individuals at least two years post ACLR compared to Healthy Controls. Methods: Running biomechanics of 74 (37 ACLR and 37 healthy control) participants all between the 18-45 years old. were evaluated. Participants performed 6 trials running at a velocity of 4.0 m/s  10% at each strobe level. Running trials were completed under 3 conditions: normal vision (S3), low SVFD (S3), and high SVFD (S7). The ACLR limb was individually matched to CON via leg dominance. Kinematics were collected at 240 Hz via 3D motion capture system (Vicon, Colorado, USA); kinetics were collected at 960 Hz using a force plate (AMTI, Massachusetts, USA). A 2 x 3 (between and within participants) mixed ANOVA design. Two groups (IV1:ACLR and CON groups) completed testing for running under normal conditions and two SVFD conditions (IV2). Gait-related loading biomechanical variables, particularly those associated with ACLR dysfunction and/or OA, with a focus on joint moments and power, served as dependent variables.Results: KAM RATE at the S0 strobe setting was significantly different (P=0.04) between ACLR and MATCHED. No other variables were significantly different between groups for any strobe levels. Comparing strobe settings within the ACLR and MATCHED groups, ACLR participants demonstrated a significant decrease in maximum vertical ground reaction force (VGRF - scaled for body mass: (n/kg)) and the peak rate of knee adduction moment (KAM RATE - calculated as the peak KAM divided by the time to reach peak KAM following initial contact during stance) while under strobe conditions. Notably, there was no significant difference in peak knee adduction moment (KAM) between ACLR and MATCHED for any of the three strobe settings nor between any of the strobe settings within either ACLR or MATCHED. There were no significant differences between strobe settings within the MATCHED group for any of the variables examined: VGRF, peak KAM, and KAM RATE. Conclusion: Individuals who have undergone ACL reconstruction on average more than 8 years prior, displayed underloading with regards to VGRF and KAM RATE when visual disruption was applied. Within the CON group, there were no signs of change in loading the knee while under visual disruption. These findings support a growing body of research suggesting that persistent long-term loading deficits following ACLR, which likely increase the risk for PTOA, may be due to overreliance on visual feedback and deficits in sensorimotor function.
Sex Differences in Long-term Running Knee Loading Mechanics Between Anterior Cruciate Ligament Reconstructed and Healthy Controls
(University of Hawai'i at Manoa, 2024) Gin, Malia Xiao; Stickley, Christopher; Kinesiology and Rehabilitation Science
Context: The prevalence of anterior cruciate ligament (ACL) injuries is increasing annually in the US, with female athletes two to eight times more likely to sustain an ACL tear than their male counterparts. Long-term biomechanical alterations in loading after anterior cruciate ligament reconstruction (ACLR) likely play a critical role in cellular and metabolic responses associated with a 3-6 times increased risk of developing osteoarthritis (OA) among ACLR patients. However, differences in long-term compensatory patterns between males and females, which may contribute to the increased rate of OA in women, have not been widely studied. Thus, the purpose of this study was to compare the effect of ACLR within females versus the effect of ACLR within males. Specifically, this study evaluated differences in running knee loading mechanics within females and males with ACLR long-term relative to their sex-matched healthy controls. Methods: Running biomechanics of participants with a history of ACLR were compared to matched controls. Six successful running trials, three for each foot, with patients running at 4.0 m/s ±10% were used for analysis. Kinematic data were collected via a 3D motion capture system (Vicon, Inc., Centennial, CO) at 240 Hz and time synchronized with kinetic data collected at 960 Hz using a force plate (AMTI, Boston, MA). Kinematic and kinetic data were filtered using a Butterworth filter with a 10Hz cut-off frequency, except for ground reaction force which was filtered at 50z and processed using Visual3D (C-Motion Inc, Germantown, MD). A 2x2 factorial model was used to identify knee moments in the sagittal and frontal planes for which the effect of ACLR differed by sex. Subsequently, post-hoc pairwise comparisons were used for variables with significant interactions from the factorial model to identify differences by group (ACLR vs. CON) and sex (Male vs. Female). For comparisons that produce a significant P-value in the post hoc pairwise analysis, statistical parametric mapping (SPM) ANOVA analyses were conducted on the respective time-normalized biomechanical waveforms across the stance phase separately for each sex to further identify differences in discrete variables throughout the entire motion and contextualize discrete variable differences. Results: The effect of ACLR on peak knee adduction moment (KAM) (interaction: P=0.041, n2:0.058), the timing of KAM within stance (KAM%) (interaction: P=0.034, n2:0.063), and KAM impulse (interaction; P=0.025, n2=0.069) was significantly different by sex. KAM was significantly higher in ACLR females compared to CON females (P= 0.043, n2= 0.057). KAM% was significantly earlier during stance in ACLR females compared to CON females (P=0.012, n2:0.086). Female ACLR exhibited decreased peak absorptive sagittal knee power (P=0.002, n2:0.131) but increased peak absorptive frontal knee power (P=0.036, n2:0.061) compared to CON females. Male ACLR exhibited a significant decrease in KAM impulse (P= 0.029, n2=0.067) with no differences in female groups. Conclusion: Females, an average of 8 years following ACLR, demonstrated increases in frontal plane knee loading represented by KAM and earlier occurrence of KAM during stance compared to CON females, which indicate increased medial compartment loading and may contribute to the marked increase in OA risk following ACLR. Earlier KAM% in ACLR females suggests abnormal overloading in an area of the articular cartilage that may not be accommodated to KAM forces. Females exhibited a force absorption strategy of decreased sagittal plane absorptive power and increased frontal plane absorptive power following ACLR suggesting absorptive forces from the sagittal plane are diverted to the frontal plane. ACLR males exhibited cumulative underloading, represented by KAM impulse which may be equally detrimental and increase the risk for cartilage degeneration. Both overloading and underloading occurring long-term following ACLR present a potential risk for degeneration of cartilage health and PTOA risk.
Effects of Head Impact Exposure in High School Football Athletes on Cognitive Performance and Symptom Prevalence
(University of Hawai'i at Manoa, 2024) Meyer, Lauren; Freemyer, Bret; Kinesiology and Rehabilitation Science
Context: High school football players may sustain hundreds of head impacts (HI) each season. Impacts to the head raise concern about their cumulative effects and long term consequences on neurocognitive function. Tackling training interventions have been shown to reduce overall head impacts and burden, but the effects of these interventions to both decrease head impacts and burden and preserve neurocognitive ability are not clear. Objective: To evaluate the effects of one season of football on neurocognitive scores as measured by the ImPACT test battery on high school football (FB) players involved in a helmetless tackling training program compared to low contact sport athletes (CON). Design: quasi-experimental, prospective cohort. Setting: Three high schools on O'ahu. Patients and Participants: 165 FB (15.3 ± 1.1 yrs) and 139 CON (15.4 ± 1.3 yrs) male participants aged 14 to 18 years old. Main Outcome Measures: ImPACT scores and symptom prevalence compared between FB and controls as well as HI and burden subgroups. Results: A difference was observed between overall FB postseason and CON baseline ImPACT scores (p=0.001). FB Verbal Memory (p=0.043) and Visual Motor Speed (p=0.018) scores were lower than CON. FB HI subgroups (p=0.047) and FB burden (p=0.028) subgroups were both different compared to CON. No univariate tests across the subgroup HI or burden analyses were significant. Post hoc testing revealed statistically significant (p<0.05) differences between groups in HI and burden subgroup analyses. Conclusion: Differences were found between FB and CON as well as HI and burden subgroups and CON, however, the effect size differences were minimal and thus, were not likely clinically significant. Therefore, football players who participated in helmetless tackling training interventions were not different from athletes who participate in non- or limited contact sports at their respective schools. FB ImPACT scores were also similar to the CON scores when grouped by differing amounts of head impacts or head impact burden. Helmetless tackling training participants may have been protected from neurocognitive changes due to overall reduced HI and burden.
Head Impact Agreement on Video Review Differs Across Rater Experience in High School Football.
(University of Hawai'i at Manoa, 2023) Roblero, Elissa J.; Freemyer, Bret; Kinesiology and Rehabilitation Science
ABSTRACT Context: Previous studies have used multiple raters for video-based reviews as a means for quantifying head impacts. However, few studies have reported on the rater's experience level and the potential influence it may have on the reliability of such video-verification methods. Objective: The purpose of this study was to assess level of agreement between two categories of raters for a video verification method of head impacts during football games. Setting: Two high school varsity football games. Participants: Eight defensive players. Main outcome measures: The definition for a video-observed head impact an obvious helmet-to-helmet, helmet-to-body, or helmet-to-playing surface impact. The video scoring consisted of four trained research personnel who reviewed a single, previously recorded game from two camera views (50-yard line and endzone). Raters participated in standardized training using separate video footage to agree on an observed head impact and to familiarize themselves with the video verification process. Two raters were certified athletic trainers with high school and college football athletic training experience and remaining two were undergraduate students without football-specific experience. No rater had any previous video analysis experience. The data were reduced by averaging the frequency count of each group and converted to 0= no head impact observed, 1= head impact observed. SPSS statistical software was used to calculate Pearson’s chi-square analyses to examine the differences in head impacts observed between the two categories of raters. Results: The chi square analysis for the first game was x2 (1) = 14.5, p <0.001 and for the second game it was x2 (1) = 23.7, p <0.001. Conclusion: The results suggest the importance of defining rater’s experience for any possible effect in accurately reporting head impacts on video analysis. Future research is needed to analyze inter-rater agreement of head impacts and comparing to head sensor data when available. The current study is important to establish research methods for video verification needed in order to understand the relationship between head impacts and risks of sport-related concussions. Word count: 341 Key words: video verification, raters, head impacts
Positional Differences In Helmet Impact Exposure Rates In Hawaiian High School Football Athletes
(University of Hawaii at Manoa, 2023) Glodowski, Kiera; Freemyer, Bret; Kinesiology and Rehabilitation Science
Context: Previous research has shown the importance of analyzing head impact exposure (HIE) among high school football players, yet few studies explore the difference across position groups. Therefore, the purpose of this study was to analyze head impact frequency between position groups.Objective: Quantify the difference of impacts per exposure (Imp/E) between position groups in high school football during the 2019 and 2021 seasons. Design: Cross-sectional study. Setting: Three high school varsity football teams on O'ahu. Patients and Participants: 200 varsity football players featuring 69 offensive/defensive linemen ( 16.0 ± 0.9 yrs, 180.4 ± 7.7 cm, 87.0 ± 22.4 kg; linemen), 51 linebackers/running backs/tight ends (16 ± 0.8 yrs, 176.6 ± 7.1 cm, 83.7 ± 13.8 kg; backers) and 80 wide receivers/defensive backs (16.1 ± 1.0 yrs, 175.4 ± 6.3 cm, 71.72 ± 10.32 kg; skills). Main Outcome Measures: Games, practice, and total Imp/E analyzed across positions, teams, and years. Results: A difference was observed across position groups (P<0.001). Season was not found to be a factor (P<0.446). A significant interaction (P<0.002) exists between team B and C (P=0.021), but not between A and C. Post-hoc analysis confirms that the backers (3.37 [95% CI: 2.80, 3.949]) experience a higher HIE compared to linemen (1.55 [95%CI: 1.067, 2.049]) and skill players (1.57 [95%CI: 1.124, 2.035]). Conclusion: To our knowledge, this is the first study of this size comparing position groups in terms of Imp/E of the given population across two seasons. These data demonstrate that linebackers and running backs experience more impacts per exposure, indicating the influence of running the ball or directly defending the ball has on increased head impacts. Future research, such as player risk-compensation, impact location across position groups in the given population, or alteration of coaching techniques and style of play could contribute to overall risk reduction of head impact exposure.Key Words: Head impact frequency, Riddell Insite, traumatic brain injury Word Count: 349 Key Points: Running backs, tight ends, and linebackers experienced a greater number of impacts per exposure in high school football players. Analyzing head impacts per exposure has the potential to identify factors contributing to increased frequency of head impacts and patterns across position groups within a team.
Utilizing Force-Velocity Profiles to Improve Athletic Performance in American Football Players
(University of Hawaii at Manoa, 2023) Ishihara, Ryan; Yamada, Paulette M. M.; Kinesiology and Rehabilitation Science
Introduction: American football requires strength, power, and speed. Force-velocity (FV) profiling describes the relationship between muscular force production and contraction velocity, and when multiplied together, the resulting product is power. FV profiling uses loaded jumps in the vertical plane and running speed in the horizontal direction to predict the imbalance between velocity and force development. Purpose: The first purpose of this study was to determine if FV profiling and optimized training improves performance metrics in American collegiate football players (i.e., countermovement vertical jump (CMJ), flying 10’s sprinting speed, 1-repetition maximum (1-RM) barbell back squat, 1-RM power clean). The second purpose was to determine if a 6-week optimized training regimen would correct FV imbalances. Methods: Eighty-two male, division-I collegiate American football athletes (20.7 ± 1.5 years old) provided written informed consent to participate in this study. Subjects were grouped by their position (i.e., offense or defense). Each subject participated in unloaded and loaded squat jumps (for vertical FV profiling) and unloaded sprints (for horizontal FV profiling). The following day, sprinting speed during a flying 10 and a full clean 1-repetition maximum (1-RM) were measured. Either 24 or 48 hours later, 2 additional performance metrics were measured: CMJ and a 1-RM back squat. Results: Of the 82 football players enrolled in the study, 50 subjects completed the protocol. The vertical FV profiling revealed that 9 athletes were velocity-deficient, 16 athletes were well-balanced, and 25 athletes were force-deficient. Descriptive statistics showed that the %FV imbalance of the velocity- and force-deficient groups decreased or increased, respectively, and each group’s imbalance moved toward the well-balanced category (90-110%). Results indicate that %FV imbalances improved as a result of the training in the velocity- and force-deficient groups, and the well-balanced group retained its well-balanced standing. Conclusion: Six weeks of individualized training was sufficient to improve performance metrics in collegiate American football players and notably, correct FV imbalances. Utilization of FV profiling catered to the individual needs of athletes as opposed to a one-size-fits-all approach, where all athletes utilize the same training program.
Helmetless Tackling Training Intervention And Preseason Self-efficacy Effects On Head Impacts In Hawaiʻi High School Football
(University of Hawaii at Manoa, 2023) Lloansi Rodriguez, Ivet; Freemyer, Bret; Kinesiology and Rehabilitation Science
Objective: Head impacts in football may be influenced by many factors, such as proper tackling and blocking techniques, years of experience, or self-efficacy. However, how these factors affect or relate to each other has not been investigated. Therefore, examining how head impacts in football are influenced by preseason self-efficacy (SE), intervention participation (IP), and years of experience (YE) playing organized tackle football may provide stakeholders with information to reduce head injuries. Design: Quantitative research consisting of a cross-sectional self-efficacy survey, a tackling training intervention, and a head impact monitoring system. Setting: Local high schools’ football fields. Participants: Initially 232 participants were recruited from five high school football teams as part of a larger study investigating the effectiveness of a helmetless tackling intervention. Final sample size of (n=120: male; n=118, female; n=2, 15.57±1.23yrs) due to incomplete >80% of one self-efficacy survey factor (response rate of 42.2%) and had incomplete head impact data. Independent Variables: preseason SE, IP, and YE playing organized tackle football. Main Outcome Measures: Self-efficacy was measured using a 53-question survey, previously validated for face and content validity, and based on Bandura’s General Self-Efficacy Scale. Questions measured level of confidence (0=no confidence, 100=highly confident) and categorized into five subscales. The accumulation of total head impacts (THI) was measured using Riddell InSite Speedflex helmets (Elyria, OH) throughout the season. An on-site research assistant recorded start/end times and participant attendance (i.e., exposure) for practices, scrimmages, and games. Head impact exposure (HIE) was standardized as a ratio of impacts per session. Multiple regression analysis tested the relationship between two dependent variables THI or HIE with seven predictor variables IP, five SE categories, and YE. Results: For THI 22.1% of the variation in the regression model was explained by the predictors (r=0.470 r2=0.221). IP had a negative correlation with THI (B=-4.480, P=0.019), while SE1 (B=3.133, P=0.010) and >8 years of experience (B=135.9, P=0.009) had a positive correlation with THI. For HIE 25.4% of the variation in the regression model was explained by the predictors (r=0.504 r2=0.254). IP had a negative correlation with number of total head impacts (B=-0.077, P=0.007), while SE1(B=3.133, P=0.010) and >8 years of experience (B=2.735, P=<0.001) had a positive correlation with HIE. Conclusions: THI and HIE are associated with players that have more than eight years of experience, have a lower number of days in IP and increased SE1 confidence scores. Players with more confidence and experience tend to engage in more risky behaviors when playing football. An early increase in the amount of time athletes spend practicing proper tackling and blocking techniques may further decrease the amount of head impacts received over time.
Force-velocity Profiles In Collegiate American Football Players
(University of Hawaii at Manoa, 2023) Hill, Parker; Yamada, Paulette M. M.; Kinesiology and Rehabilitation Science
American football is a intermittent high-intensity sport played in 3-5 seconds bursts with 20-40 seconds rest between each play. The athletic demands are position specific, but all positions require speed, agility, strength and power. Typically, strength and conditioning coaches rely on subjective observations of the athletes’ pre-season fitness or playing experience to design a training regimen. In this study, we aimed to use force-velocity profiling (FV profiling) to objectively measure performance. The first aim of this study was to determine horizontal and vertical F0(N), F0(N/kg), V0(m/s), Pmax(W), and Pmax(W/kg) in collegiate American football players and compare them between position groups. The second aim was to see if force velocity profiling could predict countermovement jump (CMJ) height and flying-10 performance. To investigate these aims we assessed 82 collegiate American football players horizontal and vertical force velocity profiles via a 30 meter sprint, unloaded jumps and loaded jumps as described by Morin and Samozino. We also assessed CMJ height, flying-10 times, squat 1-repetition max (RM) and clean 1-RM. Our results showed a moderate and positive correlation between horizontal V0(m/s) and flying-10 times. We observed a moderate and positive relationship between vertical F0(N) and squat 1-RM, clean 1-RM and CMJ. When controlling for body mass, Pmax (W/kg) had a moderate and positive correlation with CMJ in both vertical and horizontal FV profiles. Both vertical and horizontal Pmax (W/kg) also saw a moderate and negative correlation with Flying-10 performance. Horizontal and vertical FV profiling along with traditional measurements of American Football athletic performance allows the coaching staff to make better informed decisions about which training modalities should be used to improve performance.
Effects of a Fatigue Protocol on Vertical, Leg, and Joint Stiffness during Overground Running
(University of Hawaii at Manoa, 2022) Munoz, Garrett Jun; Stickley, Christopher; Kinesiology and Rehabilitation Science
Running-induced neuromuscular fatigue can alter spring-mass characteristics such as vertical, leg, and joint stiffness. The purpose of the study was to investigate the effects of a treadmill run fatigue protocol on stiffness parameters during overground running. Sixteen healthy cadets (22.4 ± 3.9 yr, 1.76 ± 0.08 m, 72.4 ± 12.3 kg) from a University’s Army Reserve Officer Training Corp were included in the study. Rested and exhausted state overground running biomechanics were collected prior to and immediately after a fatigue protocol that involved an Åstrand Protocol Graded Exercise Test and an exhaustive run at a velocity associated with 80% VO2max. No significant changes were observed for vertical, leg, or joint stiffness group means. While insignificant, knee stiffness displayed increasing trends while hip stiffness displayed decreasing trends. Leg length at initial contact (-1%, p = 0.007) and compressed leg length (-1%, p = 0.013) significantly decreased. Hip excursion (+9%, p = 0.021), change in knee moment (+7%, p = 0.027), and knee moment at the instance when the anterior- posterior ground reaction force was zero (+8%, p = 0.021) significantly increased. While running in a fatigued state, subjects attempted to maintain overall vertical and leg stiffness with joint stiffness modulations.
The Comparison Of Self-administered, Unsupervised At Home Testing And At School, Supervised Group Testing Of The Impact Baseline Composite Scores In One Interscholastic High School
(University of Hawaii at Manoa, 2021) Brothers, Darian D.; Murata, Nathan M.; Kinesiology and Rehabilitation Science
AbstractContext: Baseline concussion testing has been a common practice in head injury management, and the administration environment suggests to have an effect on the outcome scores. Due to the COVID-19 pandemic, social distancing restrictions prohibited concussion baseline testing in group settings. Objective: To compare Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) baseline scores of supervised groups to baselines taken unsupervised individually. Design: Retrospective study. Participants: 50 different individuals were selected from both the 2019-2020 and 2020-2021 school years; 2019-2020 took the baseline in a supervised group setting, 2020-2021 were unsupervised and self-administered the baseline. Both groups were from the same institution, matched by age, gender, sport, and history of concussions. Procedures: The 2019-2020 athletes took the ImPACT baseline in the institute’s library, supervised by the employed athletic trainers. The 2020-2021 athletes were given an institution specific access code to input in order to self-administer the baseline at home (or where they had computer access). MANOVA was used to compare the composite scores (verbal memory, visual memory, visual motor speed, reaction time, and impulse control) and an Independent T-test was used to compare the symptom scale. Results: No significant difference was found between the composite scores of the two groups [V = 0.45, F(5,94) = 0.89, p = .49]. One symptom score, visual problems, was deemed significantly higher in the supervised group. Conclusion: The influence of certain test administration factors can have an effect on testing outcomes for every individual and must be considered when administering concussion baseline testing. Consistent control of administration and scripted instructions in future studies will fill the gaps that remain in the debate of baseline administration. Word Count: 270
A comparison of biomechanical symmetry indices during side cutting in healthy female athletes
(University of Hawaii at Manoa, 2021) Koyama, Azumi; Freemyer, Bret; Kinesiology and Rehabilitation Science
The purpose of this study was to identify the differences and relationships between limb symmetry indices during side cutting in youth healthy female athletes. This study was the first that compared different indices during side-cutting in healthy female athletes. Symmetry indices showed less differences from each other in kinematics than kinetics. NSI following SI and SA might be recommended for clinical practices since the values of NSI stay within 100%. However, no clear advantage of NSI besides this point was observed in this study. This data could be used as normative values during side-cutting for healthy female athletes.
A Comparison Of Drop Vertical Jump Biomechanics Symmetry Indices In Healthy Females
(University of Hawaii at Manoa, 2021) Komisak, Leah; Komisak, Leah R; Kinesiology and Rehabilitation Science
ABSTRACT Asymmetrical lower extremity movement has been identified as an important risk factor in humans during gait ant and dynamic tasks in recent years. There is currently no standard symmetry assessment tool that has been validated and is clinically applicable. A new symmetry index was recently proposed – the Normalized Symmetry Index (NSI) – to serve as a possible candidate for standardizing the assessment of symmetry in dynamic tasks. This purpose of the present study is to compare the previous indices used to assess symmetry with this new index using the biomechanical data derived from healthy female athletes. All 5 indices produced varying percentages for each individual biomechanical variable. Since this study did not identify a superior index, there is no clinical recommendation for which index to use when assessing symmetry. The results produced would serve best as normative data to validate future research that will determine the best standard symmetry index.
Examining The Relationship Between Hip Strength Measures And Knee Injury Risk Factors During Side-cutting
(University of Hawaii at Manoa, 2021) Russo, Malia; Freemyer, Bret; Kinesiology and Rehabilitation Science
Anterior cruciate ligament (ACL) injuries are prevalent throughout high school, collegiate and professional athletics, with females being 2-2.5 times more likely to sustain injury compared to males. A key risk factor for non-contact ACL injury has been identified as excessive dynamic knee valgus, consisting of detrimental amounts of hip adduction and internal rotation, tibial rotation in either direction, and knee abduction. Clinical assessment of lower extremity hip strength to quantify dynamic knee valgus is of great importance. Therefore, the purpose of this research study is to investigate the relationship between hip strength measurements and knee injury risk factors during a side-cutting maneuver in females. Forty six female soccer, basketball, and volleyball athletes (age, 16.3±3.6 years; height, 1.6±0.1 m; body mass, 58.3±11.9 kg) were recruited for the research study and split into two groups (Adolescents (AD), n=27, 12-16 years; Young adults (YA), n=17, 17-25 years) . A break test was performed to using a MicroFet2 HHD (Hoggan Health Industries Inc., West Jordan, UT) to assess strength. Non-weight bearing (NWB) strength assessments included: hip external rotation (HER), hip abduction (HAB), and hip extension (HEXT). Combined weight bearing (WB) hip abductor and external rotator strength was assessed in a double leg squat bilaterally (SqB), in a double leg squat unilaterally (SqU), and in a lunge (LNG) position. A three-dimensional motion capture system (Vicon, Inc., Centennial, Colorado, USA) with 18 cameras and software (Vicon Nexus, Version 2.2.3) was utilized to capture hip and knee biomechanics during the side-cutting task. Data revealed 7/22 (32%) and 8/22 (36%) of side-cutting biomechanical variables were significantly predicted by multiple models of non-weight bearing and weight bearing hip strength assessments. Knee IR moment/(BM*HT) had the highest r² value for the NWB regression model (p = 0.007, r² = 0.378) for the AD group and was predicted by HEXT (p = 0.001, r = 0.529). In the YA group, 43% of sagittal plane knee excursion was described by HABD (p = 0.029, r = -0.658) and was the lone significant NWB regression model. Raw knee FLX moment was the lone significant WB regression model for the AD group (p = 0.002, r² = 0.444) and was predicted by SqU (p = 0.035, r = -0.503) and LNG (p = 0.035, r = 0.571). Raw vGRF had the highest r² value for the WB regression model (p = 0.004, r² = 0.625) for the YA group and was predicted by LNG (p = 0.010, r = -0.777). No consistent pattern was found. Neither strength assessment method nor individual sub-positions were found to be superior to the other in terms of predicting commonly reported knee injury risk factors. This may suggest that clinical strength assessment techniques should be multimodal to successfully examine lower extremity strength relationships, dynamic movement, and injury risk.
The Second Landing From A Drop Vertical Jump: A Biomechanical Analysis And Clinical Application To Enhance Evaluation Of ACL Injury Risk In Female Athletes
(University of Hawaii at Manoa, 2020) Letchford, Elizabeth Campbell; Stickley, Christopher; Kinesiology and Rehabilitation Science
The primary interest of the presented dissertation was to evaluate whether the second landing from a Drop Vertical Jump (DVJ) differs from the first with regards to neuromuscular control and landing mechanics in order to determine whether this second landing improves the predictive ability of clinical evaluations to properly identify athletes at risk for Anterior Cruciate Ligament (ACL) injury. Three manuscripts were completed in order to gain a more complete understanding of the relationship between the first and second landings from a drop vertical jump and their implications for injury risk evaluation. An analysis of the differences between the first and second landings according to the methodology established by the Landing Error Scoring System (LESS) was performed to gain insight into the biomechanical differences between the two tasks and to gain a better understanding of their utility. An evaluation of LESS scores associated with the first landing and the second landing was performed to determine the extent to which the individual scoring items between landings were related to each other. Finally, by investigating the ability of DVJ biomechanical variables to predict known injury risk variables during a side-cutting task, it was possible to gather insight into the relationship between the two tasks. These manuscripts represent the progression of a research agenda investigating the utility of the second landing from a drop vertical jump for the development of a more comprehensive testing scenario that better predicts an athlete’s risk for injury while being simple enough to perform on-field by Athletic Trainers and coaches.
A Biomechanical Analysis of Kinetic and Kinematic Variables in Osteoarthritic Knees Following Total Knee Arthroplasty
(University of Hawaii at Manoa, 2020) Evans, Richard; Stickley, Christopher; Kinesiology and Rehabilitation Science
Total knee arthroplasty (TKA) has become a common treatment method for combatting end-stage knee osteoarthritis (OA) in the elderly population. While level walking biomechanics have been widely studied, stair ascent and stair descent modalities remain largely in question. Biomechanical variables of interest were primarily kinetic focusing particularly on knee adduction moment (KAM) variables and moment rates. Previous research has found KAM variables to be associated with osteoarthritis in the medial compartment of the knee. The purposes of this study were twofold: 1) to compare proportional changes of each biomechanical variable from pre to post-TKA time points between level ambulation, stair-ascent, and stair-descent and 2) to determine the relationship between biomechanical variables and clinical ROM during both level and stair ambulation in an elderly population pre/post-TKA. Results of the study found KAM rate (KAM-R) to be the best discriminator amongst other KAM variables for medial knee compartment loading. The findings of this study necessitate the need for continued stair negotiation research to better understand the long-term effect of OA and TKA on a patient’s ability to negotiate stairs.
The Effects Of Quadriceps Kinesio Tape™ On Gait In Individuals With Knee Pain
(University of Hawaii at Manoa, 2020) Hu, Jingyu; Tamura, Kaori; Kinesiology and Rehabilitation Science
Purpose: To determine the effect of Kinesio Tape™ on pain and gait for people with symptomatic knee pain, when applied the Kinesio Tape™ on the quadriceps muscles. Methods: 22 participants with knee pain were randomly assigned to sham or the Kinesio Tape™ (KT) group, while 11 participants without knee pain were assigned to a control group. The control and the KT groups received the quadriceps facilitation tape method, while participants in the sham group had sham KT (without tension) application. There were four data collections: baseline, immediate post-tape, three days post-tape, and three days post-tape removal. Six walking trails were collected via 3D motion capture system. The Knee Injury and Osteoarthritis Outcome Score (KOOS) was used to assess knee pain and function. The gait variables analyzed were walking velocity, peak knee adduction angle (PKAA), peak knee adduction moment (PKAM), peak knee flexion angle (PKFA), KFA at initial contact (IC), peak knee flexion moment (PKFM), maximum vertical ground vertical force (GRF), and loading rate. Result: There were group effects for all KOOS parameters (p < 0.001) indicating the higher knee pain level and lower functionality in knee pain (KT and sham) groups, while there were time effects for walking velocity (p = 0.002) indicating learning effect for all groups. Additionally, PKAA (p = 0.004), PKFA (p = 0.027) were significantly different in the KT group; however, clinical significance remains unclear on these variables. Conclusion: Kinesio Tape™ has effects on the gait variables for individuals with knee pain, particularly for PKAA and PKFA, but it is unclear whether the effects are positive or not.
A Clinically Feasible Dual-task Assessment For Concussion Evaluation
(University of Hawaii at Manoa, 2020) Hashida, Kumiko; Tamura, Kaori; Kinesiology and Rehabilitation Science
Context: Dual-task testing (DT) using laboratory equipment has shown to detect post-concussion deficits even after traditional assessment measures returned to normal. However, little evidence supports the efficacy of clinically feasible DT as a concussion assessment tool. Objective: The purpose of this study was to compare the outcomes of clinically feasible DT between concussed and control participants. Modified Balance Error Scoring System single leg stance (mBESS SLS), mBESS tandem stance (TAN), tandem gait (TG), and Expanded Timed Get Up and Go (ETGUG) were the motor tasks and Auditory Pure Switch Task (APST) was the cognitive task. The concussed group completed data collections 7-10 days post-concussion (Time1) and after return to play (Time2). Control group completed two data collections within the same interval. Design: Mixed design. Setting: Local high school athletic training rooms and/or university laboratories. Patients or Other Participants: Concussed athletes were recruited from local high schools and a university after physician diagnosis. Matched control participants were recruited from the same institutions based on the criteria. Main Outcome Measure(s): Two ATs rated mBESS errors separately, and a mean score of the two was utilized. The TG and ETGUG was completion time (sec) and mean of the two trials for each task was utilized for analysis. Response Rate (RR) of APST was recorded as a cognitive task outcome. A mixed-model ANOVA was used with alpha level of p<0.05. Result: Nine concussed athletes and nine matched controls participated in the study. For mBESS SLS, there was no significant difference between groups under ST and DT condition at Time1 (ST: concussed 2.72±2.39 and control 2.72±2.39 , DT: concussed 2.28±3.28 and control 2.28±3.28, p=1.00) and or Time2 (ST: concussed 2.08±2.44 and control 2.08±2.44, DT: concussed 2.44±2.24 and control 2.44±2.24, p=1.00). Concussed athletes made significantly more errors during ST TAN and DT TAN than control group at both time points. Concussed group walked significantly slower than control during DT TG and ETGUG at Time1 and Time2; however, no difference was indicated with ST at both timepoints. There was a significant main effect for time, indicating learning effect for DT tandem gait for both groups; however, no learning effect was indicated for DT ETGUG. For cognitive task, no group difference was observed for all testing conditions. Conclusion: Clinically feasible DT outcomes using TG and ETGUG were significantly different between concussed and control groups at subacute phase and after return to play. In contrast, mBESS SLS and TAN performances were similar at both times in both groups. Concussed athletes took approximately 5 seconds longer to complete both tandem gait DT and ETGUG DT compared to control even after return to play. This indicated that athletes in our study returned to play before post-concussion deficits resolved. Clinically feasible DT should be considered as part of the concussion evaluation battery in addition to traditional concussion assessment. Word Count: 448 Key Words: dual-task, concussion, concussion assessment, ETGUG, tandem gait, mBESS

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