Erratum: Validity of estimating center of pressure during walking and running with plantar load from a three-sensor wireless insole - ERRATUM.

[This corrects the article DOI: 10.1017/wtc.2022.5.].

Training Load and Current Soreness Predict Future Delayed Onset Muscle Soreness in Collegiate Female Soccer Athletes.

Background: Delayed onset muscles soreness (DOMS) is an indication of muscle stress and trauma that develops from excessive musculoskeletal loads. Musculoskeletal loads can be measured with wearable devices, but there is limited research on specific training load metrics that most correlate with DOMS after activity. Purpose: To determine the predictive capabilities of training load variables on the development of lower extremity DOMS in female collegiate soccer athletes throughout an entire season. Study Design: Prospective Cohort. Methods: Twenty-seven collegiate female soccer athletes reported their lower extremity DOMS each day prior to all soccer activity. Participants wore Polar heart rate and global positioning monitors to capture training load measures. Pearson correlation coefficients were used to assess the relationships between the training load variables and change in DOMS when collapsed across dates. Separate linear mixed models were performed with the following day's DOMS as the outcome variable, training load and the current day's DOMS as predictor variables, and participants serving as random intercepts. Results: All training load variables significantly predicted change in DOMS, with number of decelerations (ρ=0.72, p <0.001), minutes spent at greater than 80% of maximum heart rate (HRmax) (ρ=0.71 , p <0.001), and distance (ρ=0.70 , p <0.001) best correlating with change in DOMS. Linear mixed models revealed a significant interaction of all training load and current day's DOMS on the following day's DOMS (p<0.001), but number of decelerations, HRmax, and total number of accelerations demonstrated the highest coefficient of determination (R2 marginal=33.2% - 29.2% , R2 conditional= 46.9% - 44.8%). Conclusions: Training load variables paired with the current day's DOMS significantly predict lower extremity DOMS in the future, with number of decelerations, accelerations, and HRmax best predicting future DOMS. Although this demonstrates that training load variables predict lower extremity DOMS, future research should incorporate objective measures of strength or jump kinetics to identify if similar relationships exist. Level of Evidence: Level 3.

Prematriculation Predictors of Academic Difficulties During the First Year of a Doctor of Physical Therapy Program.

PURPOSE: To analyze the ability of pre-matriculation metrics to predict difficulties during the first year of a Doctor of Physical Therapy (DPT) program with a pass-fail grading system. METHODS: Undergraduate cumulative, science, and pre-requisite grade point averages (GPAs) and verbal and quantitative Graduate Record Examination (GRE) percentiles were collected during the admissions process of 190 students in an accredited DPT program at a southeastern US private university between 2019-2021. Students were dichotomized to groups with and without academic difficulties in coursework and a first-year comprehensive assessment (CA). Independent t-tests identified differences between groups, and logistic regression analyses identified predictors of academic difficulties. Receiver operating characteristic (ROC) curve analyses were performed to identify cut-off scores and risk ratios were calculated. RESULTS: Students with coursework difficulties had lower verbal (d=0.36, p=0.009) and quantitative (d=0.31, p=0.02) GRE scores. Verbal GRE scores were also lower in students who failed the CA (p=0.049). Students who scored less than the 47th percentile on the verbal GRE were 53% more likely to have academic difficulties and 4.2 times more likely to fail the CA than those who scored in the 70th percentile or higher. CONCLUSION: Verbal GRE percentile best predicted academic difficulty in the first year of a DPT program.

The quality of care index for low back pain: a systematic analysis of the global burden of disease study 1990-2017.

BACKGROUND: . Low back pain is one of the major causes of morbidity worldwide. Studies on low back pain quality of care are limited. This study aimed to evaluate the quality of care of low back pain worldwide and compare gender, age, and socioeconomic groups. METHODS: . This study used GBD data from 1990 to 2017 from the Institute for Health Metrics and Evaluation (IHME) website. Extracted data included low back pain incidence, prevalence, disability-adjusted life years (DALYs), and years lived with disability (YLDs). DALYs to prevalence ratio and prevalence to incidence ratio were calculated and used in the principal component analysis (PCA) to make a proxy of the quality-of-care index (QCI). Age groups, genders, and countries with different socioeconomic statuses regarding low back pain care quality from 1990 to 2017 were compared. RESULTS: The proxy of QCI showed a slight decrease from 36.44 in 1990 to 35.20 in 2017. High- and upper-middle-income countries showed a decrease in the quality of care from 43.17 to 41.57 and from 36.37 to 36.00, respectively, from 1990 to 2017. On the other hand, low and low-middle-income countries improved, from a proxy of QCI of 20.99 to 27.89 and 27.74 to 29.36, respectively. CONCLUSION: . Despite improvements in the quality of care for low back pain in low and lower-middle-income countries between 1990 and 2017, there is still a large gap between these countries and higher-income countries. Continued steps must be taken to reduce healthcare barriers in these countries.

Preventing Osteoarthritis After an Anterior Cruciate Ligament Injury: An Osteoarthritis Action Alliance Consensus Statement.

After an anterior cruciate ligament (ACL) injury, people need secondary prevention strategies to identify osteoarthritis at its earliest stages so that interventions can be implemented to halt or slow the progression toward its long-term burden. The Osteoarthritis Action Alliance formed an interdisciplinary Secondary Prevention Task Group to develop a consensus on recommendations to provide clinicians with secondary prevention strategies that are intended to reduce the risk of osteoarthritis after a person has an ACL injury. The group achieved consensus on 15 out of 16 recommendations that address patient education, exercise and rehabilitation, psychological skills training, graded-exposure therapy, cognitive-behavioral counseling (lacked consensus), outcomes to monitor, secondary injury prevention, system-level social support, leveraging technology, and coordinated care models. We hope this statement raises awareness among clinicians and researchers on the importance of taking steps to mitigate the risk of osteoarthritis after an ACL injury.

Evidence Review for Preventing Osteoarthritis After an Anterior Cruciate Ligament Injury: An Osteoarthritis Action Alliance Consensus Statement.

CONTEXT: The Osteoarthritis Action Alliance formed a secondary prevention task group to develop a consensus on secondary prevention recommendations to reduce the risk of osteoarthritis after a knee injury. OBJECTIVE: Our goal was to provide clinicians with secondary prevention recommendations that are intended to reduce the risk of osteoarthritis after a person has sustained an anterior cruciate ligament injury. Specifically, this manuscript describes our methods, literature reviews, and dissenting opinions to elaborate on the rationale for our recommendations and to identify critical gaps. DESIGN: Consensus process. SETTING: Virtual video conference calls and online voting. PATIENTS OR OTHER PARTICIPANTS: The Secondary Prevention Task Group consisted of 29 members from various clinical backgrounds. MAIN OUTCOME MEASURE(S): The group initially convened online in August 2020 to discuss the target population, goals, and key topics. After a second call, the task group divided into 9 subgroups to draft the recommendations and supportive text for crucial content areas. Twenty-one members completed 2 rounds of voting and revising the recommendations and supportive text between February and April 2021. A virtual meeting was held to review the wording of the recommendations and obtain final votes. We defined consensus as >80% of voting members supporting a proposed recommendation. RESULTS: The group achieved consensus on 15 of 16 recommendations. The recommendations address patient education, exercise and rehabilitation, psychological skills training, graded-exposure therapy, cognitive-behavioral counseling (lacked consensus), outcomes to monitor, secondary injury prevention, system-level social support, leveraging technology, and coordinated care models. CONCLUSIONS: This consensus statement reflects information synthesized from an interdisciplinary group of experts based on the best available evidence from the literature or personal experience. We hope this document raises awareness among clinicians and researchers to take steps to mitigate the risk of osteoarthritis after an anterior cruciate ligament injury.

Women's College Volleyball Players Exhibit Asymmetries During Double-Leg Jump Landing Tasks.

CONTEXT: Women's volleyball requires frequent and repetitive jumping that when performed with altered biomechanics, including kinematic or kinetic asymmetry, may place the athlete at high risk for injury. This study identified and analyzed lower-extremity biomechanical asymmetries in college women's volleyball players during standard and sport-specific double-leg landing tasks. DESIGN: Cross-sectional laboratory study. METHODS: Eighteen female college volleyball players were analyzed using standard 3D motion capture techniques during a drop vertical jump and an unanticipated lateral reactive jump task. Repeated-measures multivariate analysis of variance identified asymmetries in kinematic and kinetic variables of each task. RESULTS: Average symmetry indices ranged from 9.3% to 31.3% during the drop vertical jump and 11.9% to 25.6% during the reactive jump task. During the drop vertical jump, the dominant limb exhibited lower knee abduction moments (P = .03), ankle dorsiflexion moments (P = .02), ankle eversion moments (P = .003) and vertical ground reaction forces (P = .03), and greater ankle inversion moments (P = .001). Both kinematic (λ = 0.27, P = .03) and kinetic (λ = 0.12, P = .008) asymmetries were identified during the reactive jump task. The dominant limb exhibited greater peak knee flexion (P = .003) and ankle dorsiflexion (P = .02) angles, and greater ankle dorsiflexion (P = .005) and inversion (P = .03) moments than the nondominant limb. CONCLUSIONS: These asymmetries observed during double-leg landing tasks may predispose volleyball athletes to unilaterally higher ground reaction or muscle forces and ultimately a greater risk of injury during landing.

Quantifying External Load and Injury Occurrence in Women's Collegiate Volleyball Players Across a Competitive Season.

ABSTRACT: Taylor, JB, Barnes, HC, Gombatto, SP, Greenwood, D, and Ford, KR. Quantifying external load and injury occurrence in women's collegiate volleyball players across a competitive season. J Strength Cond Res 36(3): 805-812, 2022-Volleyball demands repetitive jumping, with high loads linked to risk of injury. The purpose of this study was to examine jumping demands and injury patterns throughout a women's volleyball season. Sixteen Division-I female volleyball players wore an accelerometer to record jump count (JC) and jump height during every practice and match throughout the season. Physical health was documented using a weekly modified Oslo Sports Trauma Research Center Overuse Injury Questionnaire (OSLO) and time-loss injuries were recorded. Multivariate analyses of variance were used to compare measures across phases of the season, between types of session (practice vs. match), and between injured and noninjured players (α = 0.05). Results showed the greatest training demands in the preseason with larger jump counts than during the nonconference, conference schedule, and postseason schedules (p < 0.001). Performance increased throughout the season with greater jump heights in the nonconference and conference schedule than in the preseason (p = 0.01). There were no significant differences in JC between practices (65.5 ± 30.5) and matches (67.5 ± 46.4). An injury incidence of 5.49 injures per 1,000 athletic exposures was identified, with injuries accounting for 31 days lost, or 2.1% of total exposures. Injuries affected performance throughout the season, as noted by an average weekly OSLO score of 15.1 ± 13.9%. Injured players had significantly lower jump counts per exposure (p = 0.03) and a larger variation in training load than uninjured players (coefficient of variation: injured = 54%, uninjured = 41%; p = 0.006). These data help provide coaches and clinicians for training and rehabilitation program designs.

Ankle Dorsiflexion Affects Hip and Knee Biomechanics During Landing.

BACKGROUND: Restricted ankle dorsiflexion range of motion (DFROM) has been linked to lower extremity biomechanics that place an athlete at higher risk for injury. Whether reduced DFROM during dynamic movements is due to restrictions in joint motion or underutilization of available ankle DFROM motion is unclear. HYPOTHESIS: We hypothesized that both lesser total ankle DFROM and underutilization of available motion would lead to high-risk biomechanics (ie, greater knee abduction, reduced knee flexion). STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 3. METHODS: Nineteen active female athletes (age, 20.0 ± 1.3 years; height, 1.61 ± 0.06 m; mass, 67.0 ± 10.7 kg) participated. Maximal ankle DFROM (clinical measure of ankle DFROM [DF-CLIN]) was measured in a weightbearing position with the knee flexed. Lower extremity biomechanics were measured during a drop vertical jump with 3-dimensional motion and force plate analysis. The percent of available DFROM used during landing (DF-%USED) was calculated as the peak DFROM observed during landing divided by DF-CLIN. Univariate linear regressions were performed to identify whether DF-CLIN or DF-%USED predicted knee and hip biomechanics commonly associated with injury risk. RESULTS: For every 1.0° less of DF-CLIN, there was a 1.0° decrease in hip flexion excursion (r2 = 0.21, P = 0.05), 1.2° decrease in peak knee flexion angles (r2 = 0.37, P = 0.01), 0.9° decrease in knee flexion excursion (r2 = 0.40, P = 0.004), 0.002 N·m·N-1·cm-1 decrease in hip extensor work (r2 = 0.28, P = 0.02), and 0.001 N·m·N-1·cm-1 decrease in knee extensor work (r2 = 0.21, P = 0.05). For every 10% less of DF-%USED, there was a 3.2° increase in peak knee abduction angles (r2 = 0.26, P = 0.03) and 0.01 N·m·N-1·cm-1 lesser knee extensor work (r2 = 0.25, P = 0.03). CONCLUSION: Lower levels of both ankle DFROM and DF-%USED are associated with biomechanics that are considered to be associated with a higher risk of sustaining injury. CLINICAL RELEVANCE: While total ankle DFROM can predict some aberrant movement patterns, underutilization of available ankle DFROM can also lead to higher risk movement strategies. In addition to joint specific mobility training, clinicians should incorporate biomechanical interventions and technique feedback to promote the utilization of available motion.

External Match Load in Women's Collegiate Lacrosse.

ABSTRACT: Devine, NF, Hegedus, EJ, Nguyen, A-D, Ford, KR, and Taylor, JB. External match load in women's collegiate lacrosse. J Strength Cond Res 36(2): 503-507, 2022-Quantifying external loads during athletic activities, particularly game-level competition, can provide objective data for the management of athlete performance, late-stage rehabilitation, and return-to-play decisions after lower extremity injury; yet, no studies have quantified these data in collegiate women's lacrosse athletes. The purpose of this study was to report external load values for collegiate women's lacrosse players and identify positional differences in activity demands during game competition. Load data were collected on 18 collegiate women's lacrosse players using a wearable global positioning system unit during a 19-game season. Descriptive statistics of distance, speed, and frequency (sprints, high-intensity sprints, high-intensity accelerations, high-intensity decelerations) measures were computed. Linear mixed models were used to identify differences between positions and phases of the season (α = 0.05). On average, players travelled 4,733 ± 2,294 m per game (range, 1,259-7,811 m), of which 656 ± 446 m (range 60-1,633 m) occurred at high-intensity speeds and reached a maximum speed of 24.1 ± 2.6 km·h-1 (range, 19.2-27.7 km·h-1). In each game, subjects averaged 124 ± 68 sprints, 6.1 ± 4.1 high-intensity sprints, 51 ± 34 high-intensity accelerations, and 38 ± 25 high-intensity decelerations. Positional differences were identified for total (p = 0.04) and relative (p = 0.01) distance travelled at high-intensity speeds, and frequency of sprints (p = 0.01) and high-intensity decelerations (p = 0.03). During game competition, collegiate women's lacrosse demands significant external load, much of which occurs at high intensities. These data provide sport- and position-specific values for reference during late-stage rehabilitation and return-to-play testing, allowing clinicians to quantitatively progress load tolerance throughout rehabilitation and guide safe return to play.

Sex-Specific Changes in Physical Risk Factors for Anterior Cruciate Ligament Injury by Chronological Age and Stages of Growth and Maturation From 8 to 18 Years of Age.

OBJECTIVE: To critically assess the literature focused on sex-specific trajectories in physical characteristics associated with anterior cruciate ligament (ACL) injury risk by age and maturational stage. DATA SOURCES: PubMed, CINAHL, Scopus, and SPORTDiscus databases were searched through December 2021. STUDY SELECTION: Longitudinal and cross-sectional studies of healthy 8- to 18-year-olds, stratified by sex and age or maturation on ≥1 measure of body composition, lower extremity strength, ACL size, joint laxity, knee-joint geometry, lower extremity alignment, balance, or lower extremity biomechanics were included. DATA EXTRACTION: Extracted data included study design, participant characteristics, maturational metrics, and outcome measures. We used random-effects meta-analyses to examine sex differences in trajectory over time. For each variable, standardized differences in means between sexes were calculated. DATA SYNTHESIS: The search yielded 216 primary and 22 secondary articles. Less fat-free mass, leg strength, and power and greater general joint laxity were evident in girls by 8 to 10 years of age and Tanner stage I. Sex differences in body composition, strength, power, general joint laxity, and balance were more evident by 11 to 13 years of age and when transitioning from the prepubertal to pubertal stages. Sex differences in ACL size (smaller in girls), anterior knee laxity and tibiofemoral angle (greater in girls), and higher-risk biomechanics (in girls) were observed at later ages and when transitioning from the pubertal to postpubertal stages. Inconsistent study designs and data reporting limited the number of included studies. CONCLUSIONS: Critical gaps remain in our knowledge and highlight the need to improve our understanding of the relative timing and tempo of ACL risk factor development.

Validity of estimating center of pressure during walking and running with plantar load from a three-sensor wireless insole.

The purpose of this study was to determine if estimated center of pressure (COP) from plantar force data collected using three-sensor loadsol insoles was comparable to the COP from plantar pressure data collected using pedar insoles during walking and running. Ten healthy adults walked and ran at self-selected speeds on a treadmill while wearing both a loadsol and pedar insole in their right shoe. Plantar force recorded from the loadsol was used to estimate COP along mediolateral (COPx) and anteroposterior (COPy) axes. The estimated COPx and COPy were compared with the COPx and COPy from pedar using limits of agreement and Spearman's rank correlation. There were significant relationships and agreement within 5 mm in COPx and 20 mm in COPy between loadsol and pedar at 20-40% of stance during walking and running. However, loadsol demonstrated biases of 7 mm in COPx and 10 mm in COPy compared to pedar near initial contact and toe-off.

Single-Leg Vertical Hop Test Detects Greater Limb Asymmetries Than Horizontal Hop Tests After Anterior Cruciate Ligament Reconstruction in NCAA Division 1 Collegiate Athletes.

BACKGROUND: Knee function deficits may persist after anterior cruciate ligament reconstruction (ACLR). Return to sport (RTS) testing batteries assess recovery after ACLR and can guide RTS progression, but the ideal test components are debatable. The single leg vertical hop for height (SLVH) test using a commercially available jump mat may provide a valuable assessment of knee function. HYPOTHESIS/PURPOSE: The purpose of this study was to compare the limb symmetry index (LSI) of SLVH to horizontal hop testing in a cohort of National Collegiate Athletic Association (NCAA) Division 1 collegiate athletes after ACLR. The hypothesis was the SLVH would elicit significantly lower LSI than horizontal hop tests. STUDY DESIGN: Cross-Sectional Study. METHODS: Eighteen National Collegiate Athletic Association (NCAA) Division 1 collegiate athletes (7 males, 11 females) at 7.33 ± 2.05 months after ACLR were included in this retrospective study. LSI was calculated for single hop for distance (SHD), triple hop for distance (THD), cross-over hop for distance (CHD), timed 6-meter hop (T6H), and SLVH. A repeated measures ANOVA was performed to identify differences in LSI for each test. Spearman's Rho correlation coefficient was calculated to examine the relationship between LSIs for each test. RESULTS: The LSI for SLVH (84.48% ± 11.41%) was significantly lower than LSI for SHD (95.48 ± 8.02%, p = 0.003), THD (94.40 ± 3.70%, p = 0.002), CHD (95.85 ± 7.00, p = 0.007), and T6H (97.69 ± 6.60%, p = 0.001). The correlation of LSI between SLVH and the horizontal hop tests was weak and non-significant for SHD (rs = 0.166, p = 0.509), CHD (rs = 0.199, p = 0.428), and T6H (rs = 0.211, p = 0.401) and moderate and non-significant for THD (rs = 0.405, p = 0.096). CONCLUSIONS: Individuals after ACLR had lower LSI on the SLVH than on horizontal hop tests and weak to moderate correlations between the tests suggest SLVH detects performance deficits not identified by the horizontal hop tests. LEVEL OF EVIDENCE: 3.

Incorporating Internal and External Training Load Measurements in Clinical Decision Making After ACL Reconstruction: A Clinical Commentary.

BACKGROUND AND PURPOSE: Poor outcomes after anterior cruciate ligament reconstruction (ACLr), including the relatively high risk of suffering a subsequent ACL injury, suggest the need to optimize rehabilitation and return-to-sport testing. The purpose of this commentary is to introduce clinicians to the concept of monitoring training load during rehabilitation, to review methods of quantifying internal and external loads, and to suggest ways that these technologies can be incorporated into rehabilitation progressions and return-to-sport decisions after anterior ACLr. DESCRIPTION OF TOPIC WITH RELATED EVIDENCE: Quantifying and identifying the effects of training load variables, external (distance, impacts, decelerations) and internal (heart rate, heart rate variability) workload, during rehabilitation can indicate both positive (improved physical, physiological, or psychological capacity) or negative (heightened risk for injury or illness) adaptations and allow for the ideal progression of exercise prescription. When used during return-to-sport testing, wearable technology can provide robust measures of movement quality, readiness, and asymmetry not identified during performance-based testing. DISCUSSION / RELATION TO CLINICAL PRACTICE: Researchers have reported the actual in-game demands of men and women of various ages and competition levels during multi-directional sport. Wearable technology can provide similar variables during rehabilitation, home exercise programs, and during on-field transition back to sport to ensure patients have met the expected fitness capacity of their sport. Additionally, clinicians can use internal load measures to objectively monitor patient's physiological responses to rehabilitation progressions and recovery rather than relying on subjective patient-reported data. LEVEL OF EVIDENCE: 5.

EFFECTS OF SURFACE ON TRIPLE HOP DISTANCE AND KINEMATICS.

BACKGROUND: The single leg triple hop (SLTH) test is often utilized by rehabilitation practitioners as a functional performance measure in a variety of patient groups. Accuracy and consistency are important when measuring the patient progress and recovery. Administering the SLTH test on different surfaces, consistent with the patient's sport, may affect the hop distances and movement biomechanics. PURPOSE: The purpose of this study was to examine the effects of court and turf surfaces on the hop distance, limb symmetry index (LSI), and lower extremity kinematics of a SLTH test. METHODS: Recreationally active female participants (n=11, height 163.8 ± 7.1cm, mass 63.1 ± 7.1kg, age 18.9 ± 0.9yrs), without injury, volunteered to participate in the study. Three maximal effort SLTH test trials on two different surfaces (court, synthetic turf) were collected and analyzed using 3D motion analysis techniques. Outcome variables included SLTH test distances and LSI values and sagittal plane kinematics including trunk, hip, knee and ankle range of motion (ROM) during the last two landings of each SLTH test trial. The second landing involves an absorption phase and propulsion phase in contrast to the final landing which involves absorption and final balance on the single leg. Paired t-tests were used to determine differences between surfaces in hop distance and LSI values. Two-way repeated measures ANOVA were used to determine differences between surfaces in kinematic variables. RESULTS: The total SLTH test distance was not statistically different between the court (4.11 ± 0.47m) and turf (4.03 ± 0.42m, p=0.47) surfaces. LSI for the court surface was 100.8 ± 3.0% compared to 99.7 ± 3.0% for turf surface, which was not statistically different (p=0.30). Knee flexion ROM was significantly less (p=0.04) on the turf compared to the court surface during the second landing. Ankle flexion range of motion was also significantly less (p=0.03) during the second landing on turf compared to court. CONCLUSIONS: Type of surface influenced landing kinematics but not total SLTH test distance. When evaluating the quality of landings during a SLTH test, it may be warranted to observe each type of landing and the type of surface used during single leg tests. LEVEL OF EVIDENCE: 2.

INCORPORATING WORKLOAD MEASURES INTO REHABILITATION AFTER ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION: A CASE REPORT.

BACKGROUND: and purpose: Second anterior cruciate ligament (ACL) injury rates continue to be high, with a majority of injuries occurring soon after return-to-play, potentially because athletes may not be ready for the external load demands of the sport. Load metrics, tracked through wearable technology, may provide complementary information to standard limb symmetry indices in the return-to-play decision making process. The purpose of this case report was to quantify and monitor load using innovative technology during physical therapy rehabilitation after ACL reconstruction (ACLr) and compare to normative sport participation data.Case Description: The subject was a 12-year-old female soccer player that suffered an ACL injury followed by surgical reconstruction with a hamstring autograft and standard rehabilitation. Single-leg hop performance, isokinetic strength, and external loads (using wearable technology) were measured longitudinally during rehabilitation and analyzed at the time of return-to-play.Outcomes: The subject successfully achieved >90% LSI for isometric quadriceps strength (week 14), single leg hop battery (week 23), and isokinetic hamstrings (week 26) and quadriceps (week 31) strength by the time of return-to-play (week 39). At the time of return to play, external load metrics indicated that the subject's most intense rehabilitation session consisted of 36% less frequent movements, 38% lower total distances, and activity durations that were 29% lower than the expected demands of a match. DISCUSSION: Standard rehabilitation may underload patients relative to required sport demands. Measuring external load during the rehabilitation period may help clinicians adequately progress workload to the necessary demands of the patient's sport. With the current emphasis on restoring limb symmetry, clinicians may need to shift focus towards load preparation when returning a patient to their sport.Level of Evidence: 4Keywords: anterior cruciate ligament, load, rehabilitation, return to play, step count, movement system.

The single-leg vertical hop provides unique asymmetry information in individuals after anterior cruciate ligament reconstruction.

BACKGROUND: Traditional testing to identify asymmetries after anterior cruciate ligament reconstruction include four similar horizontal hopping tests. The purpose of this study was to determine whether a single-leg vertical hopping test can identify performance and biomechanical asymmetries, and whether performance asymmetries provide unique information compared to traditional tests. METHODS: Twelve women with history of anterior cruciate ligament reconstruction [age: 21.1 years (SD 3.2), height: 165.8 cm (SD 6.0), mass: 68.3 kg (SD 8.8)] completed traditional horizontal hop testing. Participants also performed a single-leg vertical hop for maximal height while instrumented for three-dimensional motion analysis. Paired t-tests were performed to identify side-to-side differences in performance variables and Spearman's rank correlations were performed of limb symmetry indices to identify whether the single-leg vertical hop test provides unique information. Repeated measures MANOVAs were performed to identify single-leg vertical hop biomechanical asymmetries. FINDINGS: Participants exhibited significant side-to-side performance differences during the single-leg vertical hop [mean difference = 0.02 m (SD 0.03), P = .04]. Only weak to moderate relationships were identified between limb symmetry indices of the single-leg vertical hop and other horizontal hopping tests. The vertical hop elicited significant asymmetries of joint kinematics (P = .04) and angular impulse (P = .04). Specifically, the involved limb showed lower peak ankle dorsiflexion (P = .004) and knee abduction (P = .02) angles, lower sagittal plane impulse at the knee (P = .02) and greater sagittal plane impulse at the hip (P = .03). INTERPRETATION: The single-leg vertical hop can identify performance and biomechanical asymmetries in individuals after anterior cruciate ligament reconstruction, potentially providing complementary information to standard horizontal hopping tests.

Effects of maturation on knee biomechanics during cutting and landing in young female soccer players.

Young female soccer players are at high risk of anterior cruciate ligament injury due to the fast-paced nature of the sport and surplus of unplanned movements during play. Neuromuscular training programs that aim to reduce this injury by targeting the associated biomechanical movements are a potential solution. While previous studies have examined the lack of dynamic knee control during landing, there are few that outline the role that maturation can play during unanticipated cutting. Therefore, the purpose of this study was to determine if young female soccer players across multiple phases of maturation exhibited the before seen differences in knee control during a drop landing as well as an unanticipated cutting task. 139 female soccer players volunteered to participate in this study and were classified in three maturational groups based on percent adult stature: prepubertal (PRE), pubertal (PUB), and post-pubertal (POST). Each group performed a drop vertical jump (DVJ) and an unanticipated cutting task (CUT). Standard 3D motion capture techniques were used to determine peak knee flexion/abduction angles and moments during each task. Within tasks, POST exhibited significantly greater peak abduction angles and moments compared to PUB/PRE. While each maturational group exhibited greater peak knee abduction angles during the DVJ compared to the CUT, peak knee abduction moments during the CUT were greater compared to the DVJ. Participants within each maturational group exhibited greater knee flexion during the DVJ compared to the CUT, however there were no differences identified between groups. During both tasks, POST/PUB exhibited greater peak knee flexion moments compared to PRE, as well as POST compared to PUB. Overall, each group exhibited significantly greater peak knee flexion moments during the CUT compared to the DVJ. These observed differences indicate the need for neuromuscular training programs that target both jumping and cutting techniques to reduce ACL injuries.

Methods of Identifying Limb Dominance in Adolescent Female Basketball Players: Implications for Clinical and Biomechanical Research.

OBJECTIVE: To identify relationships between self-reported limb preferences and performance measures for determining limb dominance in adolescent female basketball players. DESIGN: Cross-sectional cohort study. PARTICIPANTS: Forty adolescent female basketball players. INDEPENDENT VARIABLES AND MAIN OUTCOME MEASURES: Participants provided self-reported preferred kicking and jumping limbs, then completed 3 trials of a single-limb countermovement hop (HOPVER) and unilateral triple hop for distance (HOPHOR) on each limb. Each test was used to independently define limb dominance by the limb that produced the largest maximum vertical height and horizontal distance, respectively. RESULTS: Chi-square tests for independence identified a significant relationship between self-reported preferred kicking and jumping legs (χ = 7.41, P = 0.006). However, no significant relationships were found when comparing self-reported preference to measures of performance during the HOPHOR (χ = 0.33, P = 0.57) or HOPVER (χ = 0.06, P = 0.80). In addition, the 2 performance measures did not consistently produce the same definition of limb dominance among individuals (χ = 1.52, P = 0.22). CONCLUSIONS: Self-selection of the dominant limb is unrelated to performance. Furthermore, limb dominance, as defined by vertical jump height, is unrelated to limb dominance defined by horizontal jump distance. The results of this study call into question the validity of consistently defining limb dominance by self-reported measures in adolescent female basketball players.