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Purpose: To investigate knee joint function during an unanticipated cutting task between healthy and ACL-reconstructed (ACL-R) females within the same NCAA Division I collegiate female lacrosse team (WLAX) via knee mechanics and estimated vasti and hamstring muscle forces. Methods: Knee mechanics during three unanticipated cutting trials were observed using 3D motion analysis techniques for 26 healthy female lacrosse players, five which had previous history of ACL-R. Knee flexion angle and knee extensor moment were calculated via Visual3D. Modified musculoskeletal models were used to estimated vasti and hamstrings muscle forces obtained from static optimization. The 2 × 2 (group × limb) repeated measures ANOVAs were used to identify differences in knee mechanics, and vasti and hamstring muscle groups among healthy/ACL-R between their preferred and involved limbs. Results: There was an interaction between group and limb for knee extensor moment. ACL-R females had less knee extensor moments in their involved limb compared to their uninvolved limb (P< 0.001). There was also a group main effect found for knee flexion angle. ACL-R females cut with less knee flexion angle compared to healthy females (P< 0.013). No significant differences were found for estimated vasti or hamstring forces. Conclusions: These pilot results indicate that despite all female WLAX players undergoing the same strength and conditioning programming, training sessions, with the same coaching staff, differences in knee joint mechanics still exist between healthy and ACL-R players. These data should help inform larger-scaled studies investigating the impact of ACL-R on athletes within the same sports team.

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−1decrease in hip extensor work (r2= 0.28, P= 0.02), and 0.001 N·m·N−1·cm−1decrease 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−1lesser 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.

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 Res36(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.

Devine, NF, Hegedus, EJ, Nguyen, A-D, Ford, KR, and Taylor, JB. External match load in women's collegiate lacrosse. J Strength Cond Res36(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.

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.

Context: Greater knee-joint laxity may lead to a higher risk of knee injury, yet it is unknown whether results of self-reported outcome measures are associated with distinct knee-laxity profiles.Objective: To identify the extent to which multiplanar knee laxity is associated with patient-reported outcomes of knee function in healthy individuals during activities of daily living and sport.Design: Descriptive laboratory study.Setting: University research laboratory.Patients or Other Participants: Forty healthy individuals (20 men, 20 women; age 18–31 years).Main Outcome Measure(s): All participants were given the Knee Outcome Survey Activities of Daily Living Scale (KOS-ADL) and Sports Activities Scale (KOS-SAS) and subsequently measured for knee laxity in the sagittal, frontal, and transverse planes. Separate backward stepwise regression analyses were performed to determine the extent to which multiplanar knee-laxity values predicted KOS-ADL and KOS-SAS scores within each sex.Results: Women had higher magnitudes of anterior, posterior (POSTLAX), varus (VARLAX), valgus (VALLAX), and internal-rotation laxity than men and trended toward greater external rotation (ERLAX) laxity. Greater POSTLAX, less VALLAX, and greater VARLAXwas associated with lower KOS-ADL scores (KOS-ADL −4.8 POSTLAX, 3.3 VALLAX − 2.2 VARLAX 100.4, R2 0.74, P< .001) and greater POSTLAXand less VALLAXwas associated with lower KOS-SAS scores (KOS-SAS −8.2 POSTLAX, 3.6 VALLAX 96.4, R2 0.67, P< .001) in women. In men, greater POSTLAXand less ERLAXwas associated with lower KOS-SAS scores (KOS-ADL −4.7 POSTLAX, 0.9 ERLAX 96.4, R2 0.49, P< .001).Conclusions: The combination of POSTLAXwith less relative VALLAX(women) or less relative ERLAX(men) was a strong predictor of KOS scores, suggesting that a self-reported outcome measure may be beneficial as part of a preparticipation screening battery to identify those with perceived functional deficits associated with their knee laxity.

Context: Lower extremity injuries are common in basketball, yet it is unclear how prophylactic interventions affect lower extremity injury incidence rates.Objective: To analyze the effectiveness of current lower extremity injury prevention programs in basketball athletes, focusing on injury rates of (1) general lower extremity injuries, (2) ankle sprains, and (3) anterior cruciate ligament (ACL) tears.Data Sources: PubMed, MEDLINE, CINAHL, SPORTDiscus, and the Cochrane Register of Controlled Trials were searched in January 2015.Study Selection: Studies were included if they were randomized controlled or prospective cohort trials, contained a population of competitive basketball athletes, and reported lower extremity injury incidence rates specific to basketball players. In total, 426 individual studies were identified. Of these, 9 met the inclusion criteria. One other study was found during a hand search of the literature, resulting in 10 total studies included in this meta-analysis.Study Design: Systematic review and meta-analysis.Level of Evidence: Level 2.Data Extraction: Details of the intervention (eg, neuromuscular vs external support), size of control and intervention groups, and number of injuries in each group were extracted from each study. Injury data were classified into 3 groups based on the anatomic diagnosis reported (general lower extremity injury, ankle sprain, ACL rupture).Results: Meta-analyses were performed independently for each injury classification. Results indicate that prophylactic programs significantly reduced the incidence of general lower extremity injuries (odds ratio [OR], 0.69; 95% CI, 0.57-0.85; P< 0.001) and ankle sprains (OR, 0.45; 95% CI, 0.29-0.69; P< 0.001), yet not ACL ruptures (OR, 1.09; 95% CI, 0.36-3.29; P= 0.87) in basketball athletes.Conclusion: In basketball players, prophylactic programs may be effective in reducing the risk of general lower extremity injuries and ankle sprains, yet not ACL injuries.

THE SIDE BRIDGE IS AN EFFECTIVE STRENGTH AND STABILIZATION EXERCISE FOR THE CORE MUSCULATURE. THROUGH THE MODIFICATION OF THE BASE OF SUPPORT OR THE ADDITION OF MOVEMENT OUTSIDE OF THE FRONTAL PLANE, PROPRIOCEPTIVE CHALLENGES AND COUPLED EXTREMITY MOTIONS, THE SIDE BRIDGE CAN BE INDIVIDUALLY PROGRESSED TO MEET PERFORMANCE ENHANCEMENT OR REHABILITATION NEEDS AND GOALS.

PERTURBATION TRAINING FOR THE LOWER EXTREMITY INVOLVES CONTROLLED UNPREDICTABLE FORCES DIRECTED TO AN UNSTABLE SURFACE FOR IMPROVED EFFICIENCY OF STABILIZING MUSCULAR CONTRACTIONS DURING STANCE OR GAIT. IT IS A TYPE OF NEUROMUSCULAR TRAINING THAT REFINES NEURAL PATHWAYS TO PROMOTE EFFECTIVE MUSCULAR RECRUITMENT PATTERNS AND DYNAMIC JOINT STABILITY. COUPLED WITH OTHER NEUROMUSCULAR TECHNIQUES, PERTURBATION TRAINING HAS BEEN SHOWN TO BE EFFECTIVE IN PERIOPERATIVE TREATMENT OF ANTERIOR CRUCIATE LIGAMENT RUPTURE AND RECONSTRUCTION. THE EFFECTS OF TRAINING MAY ALSO BE BENEFICIAL IN THE PREVENTION AND REHABILITATION OF OTHER ATHLETIC INJURIES.