Single-leg Hop For Distance Research Articles

Cross-education improves quadriceps strength recovery after ACL reconstruction: a randomized controlled trial.

The aim of this study was to investigate the effects of concentric and eccentric cross-education (CE) on quadriceps strength and knee function recoveries after anterior cruciate ligament (ACL) reconstruction. Forty-eight patients (age: 29.5 ± 6.8 years, body mass index: 26.1 ± 3.2kg/m2) who had undergone ACL reconstruction with hamstring tendon autograft were included in the study. The patients were randomly divided into three groups when they reached four weeks post surgery: (1) concentric CE (n = 16); (2) eccentric CE (n = 16); and (3) control (n = 16). All groups followed the same post-surgical rehabilitation program for their reconstructed limb. Additionally, the two experimental groups followed eight weeks of isokinetic training for the uninjured knee at 60°/s for 3 days per week. Quadriceps maximum voluntary isometric strength (MVIC) was measured during the 4th week (pre-training), 12th week (post training), and 24th week post surgery. The single-leg hop distance and International Knee Documentary Committee (IKDC) scores were also evaluated during the 24th week post surgery. Analysis of variance was used for statistical analysis. Group-by-time interaction was significant for quadriceps MVICs for reconstructed and healthy limbs (p = 0.02). Quadriceps strength of both knees was greater in concentric and eccentric CE groups compared to control group during the 12th- and 24th weeks post surgery (p < 0.05). Strength gain was 28% and 31% in concentric and eccentric CE groups, respectively, when compared with the control group. Concentric and eccentric CE had similar effects on quadriceps strength recovery (n.s.). IKDC score, and single-leg hop distances were not significantly different among groups (n.s.). Concentric and eccentric quadricep strengthening of healthy limbs in early phases of ACL rehabilitation improved post-surgical quadriceps strength recovery of the reconstructed limb. CE should be integrated into ACL reconstruction rehabilitation, especially in the early rehabilitative phases to restore quadriceps strength. Randomized controlled trial, Level I.

Évaluation fonctionnelle isocinétique et neuromusculaire du genou, retour au sport après reconstruction du ligament croisé antérieur. Étude prospective d’une cohorte de 234 sportifs au recul moyen de 6 mois

BackgroundTen percent or less reduction in isokinetic and functional test performance in comparison with the healthy side is generally considered to be a sign of satisfactory functional recovery after reconstruction of the anterior cruciate ligament (ACL). The main objective of this work was to assess postoperative functional recovery of the knee joint in a large cohort. MethodsThis was a single-center prospective cohort recruited from 2012 among patients undergoing ACL repair performed by four surgeons. A retrospective analysis of data included a series of athletes who underwent the procedure in 2013–2016 for primary ACL tear, had a healthy contralateral knee, and had had postoperative functional tests. Isokinetic tests measured flexion and extension strength: concentric quadriceps 60°/s (Q60°) and 240°/s (Q240°); excentric hamstrings 30°/s (HS30°). Four single leg hop tests were performed: single leg hop for distance (SH), triple hop for distance (TH), cross-over hop for distance (CH), and single leg 6m timed-hop (6mH). The main outcome was postoperative functional recovery (yes/no) defined as≤10 % for Q60° and SH. ResultsThe study included 234 patients; mean age 28.4±8.6 years. At 6.5±1.7 (4–12) months, 44 patients (18.5 %) had recovered satisfactory function, 52 (21.8 %) at Q60° and 125 (54.3 %) at SH. During follow-up there were four cases of recurrent tears in the group with unsatisfactory functional recovery. ConclusionSix-months after ACL reconstruction, functional recovery of the knee joint is generally not satisfactory and appears to constitute a risk factor for recurrent tear.

Examining the Relationships Between the Mode of Quadriceps Contraction and Clinical Outcomes After ACL Reconstruction

Quadriceps strength is a useful clinical predictor of physical function and patient reported outcomes after anterior cruciate ligament reconstruction (ACLR). However, it remains unknown which mode of muscle contraction (isometric, concentric or eccentric) is most important for optimal physical and patient reported recovery, creating uncertainty amongst clinicians as to the most ideal strength assessment tool. PURPOSE: Examine the association between the mode of quadriceps muscle contraction (isometric, concentric and eccentric) and functional performance and patient reported outcomes. METHODS: Ten individuals with history of unilateral ACLR volunteered (22.4±1.95yrs; 1.66±0.08m; 65.62±12.10kg; years from surgery, 5.88±1.86yrs). Peak concentric and eccentric quadriceps force production at 60°/s and peak isometric force production with the knee positioned at 90° were assessed via an isokinetic dynamometer and normalized to body mass. Objective clinical hop tests were evaluated for maximal distance during the single leg hop for distance (SLHD), cross-over hop (CH) and triple hop (TrH). Patient reported outcomes were assessed using the International Knee Documentation Committee (IKDC) form. Association between quadriceps strength outcomes and all functional and patient reported outcomes were assessed using Pearson product moment correlations. RESULTS: Peak concentric strength was only associated with maximal TrH distance (mean±SD; 1.90±0.57Nm/kg, 4.61±0.67m; r=0.723, P=0.018). Peak eccentric strength was only associated with maximal SLHD (2.82±0.78Nm/kg, 1.41±0.19m; r=0.680, P=0.044). Peak isometric strength was associated with maximal CH distance (3.06±0.59Nm/kg, 4.35±0.70m; r=0.696, p=0.025) and IKDC (84.94±9.92; r=0.803, P=0.005). CONCLUSION: No single mode of quadriceps contraction was associated with all clinical outcome measures. Hence, a multimodal approach to strength re-training and evaluation may be important for the development of proper quadriceps function and progression of optimal clinical outcomes. Clinicians should consider adding a multimodal strength program during ACLR rehabilitation to promote positive outcomes across a variety of clinical measures.

Relationship between Single Leg Hop Distance and Descending Phase Force Variables

Anterior single leg hop for distance (SLHOP) is a common functional assessment used to evaluate lower extremity power and dynamic postural stability. Peak force and rate of force development (RFD) have been used to quantify strength and power, but little is known of the relationship between these measures and SLHOP distance. PURPOSE: To determine the relationship between vertical and anterior force variables during the descending phase and SLHOP distance. METHODS: Twenty-three female collegiate soccer players (19.1±1.5 years; 166.9±7.1 cm; 62.6±8.3 kg) performed SLHOP for maximal distance on their dominant limb, taking off a tri-axial force plate. Kinetic data were collected during the descending phase of the SLHOP to identify peak force in the vertical (Fz) and anterior-posterior (Fy) axes and average rate of force development (RFD), the rate of change in the force-time curve. Two start events were used to calculate RFD: 1) RFDnegative: point of maximum center of mass downward acceleration (subject moving down, acceleration negative) and 2) RFDzero: point when ground reaction force equals body weight (subject moving down, acceleration zero). The RFD end event was peak force (near the lowest point of descending). Forces were normalized to body weight and SLHOP distances were normalized to leg length. A linear regression with best subset selection method was performed to identify which combination of variables were most related to SLHOP distance with an alpha level set a priori at p<0.05. RESULTS: Peak Fy (Beta=189.32, 95%CI=133.04, 245.61, p<0.001) and RFDzero in the vertical axis (Beta=-2.94, 95%CI=5.48, -0.40, p=0.03) were significantly related to SLHOP distance (model adjusted R2=0.69). CONCLUSION: Female soccer players who maximized anterior force and minimized vertical RFD during the descending phase of SLHOP achieved greater SLHOP distances. Results suggest maximal SLHOP distance warrants both vertical and anterior force generation. However, these movement strategies may not translate across different jump tasks (i.e. vertical jump, etc.) or different sports. Further research is warranted to examine the relationship between force and RFD profiles and other jump tasks. Future studies should examine the effect of sex and sport on the relationship between SLHOP distance and force variables.

Relationship between Take-Off Force Profiles and Single Leg Hop Distance

The anterior single leg hop for distance test (SLHOP) is a functional performance task that is often used to assess return to play criteria following ACL reconstruction. Clinicians primarily assess SLHOP distance, but the way an individual completes the task may be important when determining return to play status. Recent research has indicated that non-uniformity in vertical ground reaction force (VGRF) profiles may be related to pathomechanics during a vertical jump, but little research has been done to explore the relationship between force profiles and SLHOP distance. PURPOSE: To determine the correlation between a force profile ratio and SLHOP distance. METHODS: Twenty-three female collegiate soccer players (19.1±1.5 years; 166.9±7.1 cm; 62.6±8.3 kg) performed three SLHOP tests for maximal distance off a tri-axial force plate. The SLHOP was performed on the dominant limb. Ground reaction force (GRF) data were collected during SLHOP take-off phase to produce force-time curves that were used to calculate the ratio between the instantaneous and average force profile between three events. Force profile ratios were calculated between: A) the minimum GRF after initiation of the countermovement and the peak GRF prior to takeoff, and B) the point during the countermovement when body weight is reached and peak GRF. Ratio A and B where calculated in both the vertical (z) and anterior-posterior (y) axes. All forces were normalized to body weight, and SLHOP distances were normalized to leg length (cm/cm). The strength of the association between each of the aforementioned force profile ratios and maximum SLHOP distance were calculated using Pearson correlation coefficients with an alpha level set a priori at p<0.05. RESULTS: There were no significant correlations between any combination of force profile ratios and SLHOP distance (p-value range:0.19 to 0.62, r range: -0.11 to -0.26). CONCLUSION: Force profile ratios between straight-line and trace-line distance are not significantly related to average or maximum SLHOP distance. Further research should explore the relationship between other phases within the force-time curve, pathomechanics, and SLHOP distance.

COMPARISON OF CLINICAL FATIGUE PROTOCOLS TO DECREASE SINGLE-LEG FORWARD HOP PERFORMANCE IN HEALTHY INDIVIDUALS

Return to activity decisions after anterior cruciate ligament reconstruction (ACL-R) are limited by functional performance tests often performed in a non-fatigued state. Fatigue can improve test sensitivity, but current methods to induce fatigue are typically bilateral tasks or focus on the quadriceps muscle in isolation. To determine the effects of a two-minute lateral step-down fatigue test compared to a 30-second side-hop test on single-leg forward hop distance in healthy individuals. It was hypothesized that participants would demonstrate decreased hop distance with both tests, but the two-minute lateral step-down fatigue test would result in greater deficits in single-leg forward hop distance. Randomized crossover. Twenty healthy participants (16 females, 4 males; age = 23.7±3.0 years, height = 153.8±36.2 cm; mass = 64.4±12.8 kg; Tegner = 6.8±1.2) were asked to perform single-leg forward hop for distance pre- and post-fatigue. Participants were randomly assigned to one of the two fatigue tests, 30-second side-hop or 2-minute lateral step-down test, during the first visit. They returned within a week and performed the same sequence of tests but underwent whichever fatigue test was not assigned at the prior visit. There was a significant decrease (p < 0.001) in single-leg forward hop distance following the 30-second side-hop test (pre = 134.1±23.7 cm, post = 126.2±24.4 cm) and the two-minute lateral step-down test (pre = 135.0±26.1 cm, post = 122.7±27.4 cm). The decrease in hop distance was significantly greater (p < 0.001) for the two-minute lateral step-down test compared to the 30-second side-hop test. The two-minute lateral step-down test resulted in a greater decrease in hop performance compared to the 30-second side-hop test. The results establish a threshold for expected changes that occur in a healthy population and that can then be compared with an injured athlete population. The two-minute lateral step-down exercise may be an effective method of inducing fatigue to better mimic performance in a sports environment to inform return-to-sport decisions. Level 1b- Therapy.

Hop Distance Symmetry Does Not Indicate Normal Landing Biomechanics in Adolescent Athletes With Recent Anterior Cruciate Ligament Reconstruction.

Background Return-to-sport protocols after anterior cruciate ligament reconstruction (ACLR) often include assessment of hop distance symmetry. However, it is unclear whether movement deficits are present, regardless of hop symmetry. Objectives To assess biomechanics and symmetry of adolescent athletes following ACLR during a single-leg hop for distance. Methods Forty-six patients with ACLR (5-12 months post surgery; 27 female; mean ± SD age, 15.6 ± 1.7 years) were classified as asymmetric (operative-limb hop distance less than 90% that of nonoperative limb [n = 17]) or symmetric (n = 29) in this retrospective cohort. Lower extremity biomechanics were compared among operative and contralateral limbs and 24 symmetric controls (12 female; mean ± SD age, 14.7 ± 1.5 years) using analysis of variance. Results Compared to controls, asymmetric patients hopped a shorter distance on their operative limb (P<.001), while symmetric patients hopped an intermediate distance on both sides (P≥.12). During landing, the operative limb, regardless of hop distance, exhibited lower knee flexion moments compared to controls and the contralateral side (P≤.04), with lower knee energy absorption than the contralateral side (P≤.006). During takeoff, both symmetric and asymmetric patients had less hip extension and smaller ankle range of motion on the operative side compared with controls (P≤.05). Asymmetric patients also had lower hip range of motion on the operative, compared with the contralateral, side (P = .001). Conclusion Both symmetric and asymmetric patients offloaded the operative knee; symmetric patients achieved symmetry, in part, by hopping a shorter distance on the contralateral side. Therefore, hop distance symmetry may not be an adequate test of single-limb function and return-to-sport readiness. J Orthop Sports Phys Ther 2018;48(8):622-629. Epub 30 Mar 2018. doi:10.2519/jospt.2018.7817.

A prospective investigation to evaluate risk factors for lower extremity injury risk in male youth soccer players.

There is an inherent risk of injury in male youth football; however, pertinent risk factors for injury have yet to be examined. This study used a prospective cohort design with 357 elite male youth football players (aged 10-18years) assessed during the preseason period and then monitored during the season recording all non-contact lower extremity injuries. Screening tests included single leg hop for distance (SLHD); 75% of maximum hop and stick (75%Hop); single leg countermovement jump (SLCMJ); and the tuck jump assessment (TJ). Players were divided into subgroups based on chronological age. SLCMJ peak landing vertical ground reaction force (pVGRF) asymmetry was the most prominent risk factor (U11-U12s, OR 0.90, P=.04; and U15-U16s, OR 0.91, P<.001). Maturational offset (OR 0.58, P=.04), lower right leg SLCMJ pVGRF relative to body weight (OR 0.36, P=.03), and advanced chronological age (OR 3.62, P=.04) were also significantly associated with heightened injury risk in the U13-U14s, U15-U16s, and U18s, respectively. Univariate analyses showed combinations of anthropometric and movement screening risk factors were associated with heightened risk of lower extremity injury; however, there was variability across the different chronological age groups. Greater SLCMJ pVGRF asymmetry, lower right leg SLCMJ pVGRF %BW, later maturation, and advanced chronological age are potential risk factors for injury in elite male youth football players, although the strength of these relationships was often low to moderate. In addition, risk factors are likely to change at different stages of development.

Is poor proprioception associated with worse movement quality of the knee in individuals with anterior cruciate ligament deficiency or reconstruction?

[Purpose] To investigate the association between proprioception and a knee medial to foot position during weight-bearing activities in patients with anterior cruciate ligament reconstruction and anterior cruciate ligament deficiency. [Participants and Methods] Thirty-eight patients with anterior cruciate ligament reconstruction and 13 patients with anterior cruciate ligament deficiency aged 18–40 years were included. Proprioception was assessed by knee kinesthesia measured by the threshold to detection of passive motion. Movement quality was assessed by visual observation of the position of the knee in relation to the foot during the mini squat, the single-leg hop for distance, and the cross-over hop for distance. [Results] In patients with anterior cruciate ligament deficiency, worse kinesthesia was significantly associated with a knee medial to foot position during the single-leg hop for distance. No statistically significant associations were observed between kinesthesia and a knee medial to foot position during the three tasks in patients with anterior cruciate ligament reconstruction. [Conclusion] Poor proprioception may be associated with worse movement quality of the knee in patients with anterior cruciate ligament deficiency, but not in patients with anterior cruciate ligament reconstruction. Differences in sensorimotor function between patients with reconstructed and non-reconstructed anterior cruciate ligament should be considered in training and rehabilitation regimens aiming to enhance performance and prevent further injuries in these patients.

Sports Physical Therapy Section Poster Presentations (Abstracts SPO1-SPO166).

These abstracts are presented here as prepared by the authors. The accuracy and content of each abstract remain the responsibility of the authors. In the identification number above each abstract, SPO designates a Sports Physical Therapy Section poster presentation. J Orthop Sports Phys Ther 2018;48(1):A203-A276. doi:10.2519/jospt.2018.48.1.A203.

Relationship Between Physical Therapy Characteristics, Surgical Procedure, and Clinical Outcomes in Patients After ACL Reconstruction.

Postoperative rehabilitation is critical to optimize outcomes after anterior cruciate ligament reconstruction (ACLR). However, the relationship between physical therapy (PT) and clinical outcomes is unclear. To describe PT characteristics following ACLR and to assess the relationships between PT characteristics, surgical procedure, and clinical outcomes. Cross-sectional. Laboratory. Patients (or Other Participants): A total of 60 patients (31 females/29 males, age = 22.4 [9.2]y, height = 171.7 [9.9]cm, and mass = 70.2 [14.7]kg) with a history of primary unilateral ACLR (53.6% patellar tendon and 46.4% hamstring) participated. Patients completed a performance assessment and rated subjective knee function prior to physician clearance (mean = 6.3 [1.3]mo postoperatively) and were contacted within 6 months of clearance to complete a PT questionnaire. PT questionnaire item response, knee extension maximum voluntary isometric contraction (MVIC) torque, peak isokinetic knee extension torque, single leg hop distance, and International Knee Documentation Committee were measured. Correlations assessed relationships between PT quantity and clinical outcomes. Independent t tests compared PT quantity and clinical outcomes based on return-to-sport status, readiness to return to sport, and surgical procedure. Patients completed regular PT (2d/wk, 25wk, 58 visits) and were most likely to conclude when discharged by the therapist (68.3%). More than half (56.7%) returned to sport, yet most (73.3%) felt unready at discharge. Isokinetic torque was correlated with days of PT/week (r = .29, P = .03). Isokinetic torque and hop symmetry were reduced in patients who returned to sport (P < .05). Patients who felt ready to return completed fewer weeks of PT (P < .05). Patients with a patellar tendon graft completed more days of PT/week and total visits, but demonstrated lower MVIC torque, MVIC symmetry, and isokinetic symmetry (P < .05). Many patients felt unready to return to sport at PT discharge. PT frequency was associated with isokinetic torque, yet this relationship was small. Outcomes were reduced in patients who returned to sport, suggesting premature resumption of preinjury activity.

The Effects of Maturation on Measures of Asymmetry During Neuromuscular Control Tests in Elite Male Youth Soccer Players.

Asymmetry is a risk factor for male youth soccer players. There is a paucity of data confirming the presence of asymmetry using practically viable screening tasks in players at different stages of maturation. A cross-sectional sample (N = 347) of elite male youth soccer players who were either pre-, circa-, or post-peak height velocity (PHV) completed the following assessments: single-leg Y-Balance anterior reach, single-leg hop for distance, single-leg 75% hop and stick, and single-leg countermovement jumps. Single-leg countermovement jumps landing force asymmetry was higher in both circa- and post-PHV groups (P < .001; d = 0.41-0.43). Single-leg 75% hop and stick landing force asymmetries were also highest in circa-PHV players, but between-group comparisons were not statistically significant and effect sizes were small. Single-leg hop for distance and single-leg Y-Balance anterior reach asymmetries reduced with maturation; however, no group differences were significant, with small to trivial effect sizes (d ≤ 0.25). Stage of maturation did not have a profound effect on asymmetry. Between-limb differences in functional performance seem to be established in early childhood; thus, targeted interventions to reduce this injury risk factor should commence in pre-PHV athletes and be maintained throughout childhood and adolescence to ensure asymmetry does not increase.

Reference values for fatigued versus non-fatigued limb symmetry index measured by a newly designed single-leg hop test battery in healthy subjects: a pilot study

PurposeThere is sparse evidence for return to sport criteria after knee injury. Functional performance deficits, particularly in fatigued muscular condition, should be verified prior to the attempt to return to high-risk pivoting sports. The purpose of this study was to generate reference values for the limb symmetry index (LSI) of healthy subjects in fatigued and non-fatigued muscular condition in a newly designed test battery.MethodsForty-two healthy subjects [22 females, 20 males; mean (SD) age 30.4 (6.6) years] were evaluated using a test battery consisting of an isometric strength test, a series of five single-leg hop tests and an integrated fatigue protocol. Subjective physical activity was assessed with the Tegner Activity Scale (TAS). The cut-off values for healthy subjects were calculated considering the fifth percentile as the minimum reference value for the LSI and single-leg hop distance.ResultsThe mean (SD) overall LSI was 98.8% (4.6). No significant gender or age specific differences in limb symmetry were observed. The comparison of the non-fatigued LSI with the overall LSI revealed no clinically relevant change due to muscular fatigue. Repeated measures ANOVA revealed a significant within effect on fatigue/non-fatigue condition (F(1,38) = 18.000; p < 0.001, η2 = 0.321) on absolute single-leg hop distance. Moreover, a significant between effect on the TAS-parameter (F(1,38) = 5.928; p = 0.020, η2 = 0.135 between: TAS ≤ 5/TAS > 5) and on gender (F(1,38) = 23.956; p < 0.001, η2 = 0.387) could be detected.ConclusionsThe absolute jumping distance in the single-leg hop for distance was significantly reduced due to fatigue. No clinically relevant effect of muscular fatigue was observed on limb symmetry in our study sample. Gender and physical activity are important factors to be considered when interpreting reference values.

A Comparison of Nonoperative and Operative Treatment of Complete Proximal Hamstring Ruptures.

Background:The early repair of acute proximal hamstring ruptures provides better clinical results than delayed repair. However, it is unclear how nonoperative treatment compares with the operative treatment of these injuries.Purpose:To compare the clinical results of the nonoperative and operative treatment of acute proximal hamstring ruptures.Study Design:Cohort study; Level of evidence, 3.Methods:A total of 25 patients with complete, retracted proximal hamstring ruptures presenting to 1 institution were retrospectively reviewed. All patients were given the option of proximal hamstring repair at the time of the initial evaluation. Patients with at least 12 months of follow-up from the time of surgery or injury were included in the evaluation. Both nonoperative and operative treatment groups were evaluated using the same outcome measures. The primary outcome measure was the Lower Extremity Functional Scale (LEFS). Secondary outcome measures included the Short Form–12 (SF-12) physical and mental component summaries, strength testing, a single-leg hop test, the patient’s perception of strength, and the ability to return to activity.Results:There were 11 patients treated nonoperatively, with a mean follow-up of 2.48 ± 3.66 years, and 14 patients treated operatively, with a mean follow-up of 3.56 ± 2.11 years. The mean LEFS scores for the nonoperative and operative groups were 68.50 ± 7.92 and 74.71 ± 5.38, respectively (P = .07). No statistical differences were found between the groups regarding SF-12 scores and mean single-leg hop distance compared with the uninjured leg. Isometric testing of the injured hamstring in the nonoperative group demonstrated significant clinical weakness compared with the uninjured side at both 45° and 90° of flexion (57.54% ± 7.8% and 67.73% ± 18.8%, respectively). Isokinetic testing of the injured leg in the operative group demonstrated 90.87% ± 16.3% strength of the uninjured leg. All patients in the operative group were able to return to preinjury activities, whereas 3 patients in the nonoperative group were unable to return (chi-square = 4.33, P = .07).Conclusion:Patients with acute proximal hamstring ruptures treated surgically regained approximately 90% strength of the uninjured extremity and tended to have a greater likelihood of returning to preinjury activities than patients treated nonoperatively.

Measurement Properties of a Test Battery to Assess Postural Orientation During Functional Tasks in Patients Undergoing Anterior Cruciate Ligament Injury Rehabilitation.

Study Design Cross-sectional study. Background Visual rating of postural orientation during functional tasks may be a valuable tool to track rehabilitation progress following anterior cruciate ligament (ACL) injury. A valid test battery assessing postural orientation as a separate construct is lacking. Objectives To evaluate measurement properties of a test battery to assess postural orientation in patients with ACL injury. Methods The content validity of functional tasks was assessed by expert focus group discussions. Fifty-one patients (45% women) with ACL injury performed 9 functional tasks of varying difficulty. Interpretability, internal consistency, interrater reliability, and measurement error were assessed for segment-specific postural orientation errors (POEs), within-task POEs, and total POE score. Postural orientation errors were scored on video on an ordinal scale from 0 (no POEs) to 3 (major POEs). Results Stair ascent, deep squat, and crossover hop for distance were excluded in focus group discussions. Postural orientation errors in some tasks were excluded due to floor effects. The mini-squat and drop jump were excluded due to poor internal consistency (α≤.184). Interrater reliability values for segment-specific POEs and within-task POEs yielded fair to almost perfect agreement (κ = 0.429-0.875) and almost perfect agreement for total POE score (intraclass correlation coefficient = 0.842), without systematic differences between raters. The smallest detectable changes were 0.7 and 5 points for groups and individuals, respectively. Conclusion The final test battery (single-leg mini-squat, stair descent, forward lunge, single-leg hop for distance) of 4 POEs (foot pronation, medial knee-to-foot position, hip joint POEs, and trunk segment POEs) demonstrated good measurement properties in people with ACL injury. J Orthop Sports Phys Ther 2017;47(11):863-873. doi:10.2519/jospt.2017.7270.

Associations Among Quadriceps Strength and Rate of Torque Development 6 Weeks Post Anterior Cruciate Ligament Reconstruction and Future Hop and Vertical Jump Performance: A Prospective Cohort Study.

Study Design Prospective cohort. Background Quadriceps strength is associated with hop distance and jump height in persons who have undergone anterior cruciate ligament (ACL) reconstruction. However, it is unknown whether the ability to rapidly generate quadriceps torque in the early phase of recovery is associated with future hopping and jumping performance in this population. Objective To evaluate the prospective associations among quadriceps strength and rate of torque development (RTD) and single-leg hop for distance, vertical jump height, vertical ground reaction force (vGRF), and vertical force loading rate during a landing task in persons who have undergone ACL reconstruction. Methods Seventy patients with unilateral ACL reconstruction participated. At 6 weeks post ACL reconstruction, isometric quadriceps strength and RTD were measured using a dynamometer. At 6 months following ACL reconstruction, patients performed the single-leg hop for distance test. Patients also performed the single-leg vertical jump test on a force plate that measured maximum jump height, vGRF, and average loading rate during landing. Results Both quadriceps strength and RTD at 6 weeks post ACL reconstruction were associated with all hopping and jumping measures at 6 months post ACL reconstruction (P≤.04). Single-leg hop distance was associated more closely with quadriceps strength than with quadriceps RTD (P = .05), and vertical jump height and vGRF measures were associated more closely with quadriceps RTD than with quadriceps strength (P = .05 and P<.01, respectively). Both quadriceps measures were associated with loading rate. Conclusion Quadriceps strength and RTD are complementary but distinct predictors of future hopping and jumping performance in persons who have undergone ACL reconstruction. These findings may contribute to improved rehabilitation of patients who are at risk for poor jumping/hopping performance and abnormal knee loading. J Orthop Sports Phys Ther 2017;47(11):845-852. Epub 13 Oct 2017. doi:10.2519/jospt.2017.7133.

Single-Shot Femoral Nerve Block Does Not Cause Long-Term Strength and Functional Deficits Following Anterior Cruciate Ligament Reconstruction

To determine if patients treated with a single-shot femoral nerve block have strength and functional deficits at 9-month follow-up. Forty-three patients who underwent primary anterior cruciate ligament reconstructions were randomized to receive either a preoperative single-shot femoral nerve block or local infiltration anesthesia for primary pain control. All patients underwent a standardized comprehensive rehabilitation program postoperatively. Isokinetic strength and function was tested using a Biodex machine at 9months or more postoperatively comparing the operative and nonoperative extremity. No significant difference in strength was found at an average of 10.6months postoperatively (range, 9-15months) between the femoral nerve block and control groups. In comparing strength deficits, we found no difference in slow isokinetic extension strength (22.4% vs 27.8%, P= .51), fast isokinetic extension strength (18.5% vs 12.5%, P= .41), slow isokinetic flexion strength (11.0% vs 15.1%, P= .55), and fast isokinetic flexion strength (8.2% vs 4.9%, P= .56) in the femoral nerve block versus control groups, respectively. In terms of functional outcomes, there also was no difference in deficits for single-leg hop distance (P= .12), timed single-leg hop (P= .74), and single-leg triple hop distance (P= .94). Maximal strength noted to be within 15% of the contralateral limb was achieved in 40% of patients and maximal function in 63% of patients at an average of 10.6months postoperatively. A 13% complication rate was found in patients who received a femoral nerve block (1 with prolonged quadriceps inhibition and 2 with prolonged sensory disturbances). Our study found a 13% motor/sensory complication rate in patients who underwent femoral nerve block for pain control after anterior cruciate ligament reconstruction. Although these deficits may persist, they are not permanent and are not different when compared with controls at 9-month follow-up. However, maximal strength and function are not fully restored at normal return to play time and rehabilitation should continue long term to maximize recovery. Level I, prospective randomized trial.

Hopping and Landing Performance in Male Youth Soccer Players: Effects of Age and Maturation.

Quantifying hopping and landing performances can assist coaches in identifying young male soccer players who may be at increased risk of injury. The influence of chronological age and maturation on these measures in this population is unknown. Single leg hop for distance (SLHD) and 75% horizontal hop and stick landing force (75%Hop) were examined in a cross-sectional sample (N=400) of elite male youth soccer players. Between-group differences for both chronological age (U11-U18) and stage of maturation (pre-, circa- or post-peak height velocity (PHV)) were analyzed. Absolute 75%Hop increased with both age and maturation. Apart from the U18s, pre-PHV and U11-U12 players displayed the greatest relative landing forces compared to all other groups (p<0.001; d=0.56-0.93). Absolute and relative SLHD were greatest in the U18s and post-PHV players (p<0.001; d=0.35-2.04). A trend showed increased SLHD with each consecutive age group although a reduction in performance was identified in the U13s (d=0.50-0.59). High volumes of accumulated soccer participation in the U18s may lead to altered landing strategies indicative of high injury risk. A temporary reduction in hop performance in the U13s may also be linked to a period of adolescent awkwardness.

Test-Retest Reliability of Functional Tasks in Healthy High School Athletes

The 4th edition of the Pre-Participation Physical Evaluation (PPE) recommends functional testing for the musculoskeletal portion of the examination. However, limitations exist concerning currently recommended functional test components and the feasibility of implementing this test battery in the secondary school setting. In particular, test-retest reliability for recommended functional tests across secondary school settings has yet to be established. PURPOSE: Determine test-retest reliability of three functional tests utilized in the Functional Pre-Participation Physical Evaluation (FPPE) project. METHODS: A convenience sample of four high schools currently enrolled in the FPPE project participated. Prior to the start of their competitive sports seasons, high school athletes completed a weight-bearing lunge to assess ankle dorsiflexion range of motion (DF) as well as the single leg anterior reach (SLAR) and anterior single leg hop for distance (SLHOP) tests as part of the FPPE project. Athlete testing was conducted by the head Certified Athletic Trainer (AT) at each high school and was repeated one week after the initial test date. Intraclass correlation coefficients (ICC) using a two-way mixed effects model and an absolute agreement definition were calculated for each functional test. Separate ICCs were calculated for each AT. ICC(3,1) values were interpreted as: excellent (>0.75), fair to good (0.40-0.75), and poor (<0.40). RESULTS: 40 athletes (m/f= 23/17, 16.4±1.1 y, 1.78±0.11 m, 70.1±13.1 kg) participated in this study (10 athletes per high school). Test-retest reliability was excellent for all raters for both the DF (ICC(3,1) range: 0.817-0.975) and SLHOP tests (ICC(3,1) range: 0.832-0.963). Test-retest reliability of the SLAR was found to be excellent for two raters (ICC(3,1): 0.813, 0.876) and fair to good for two raters (ICC(3,1): 0.583,0.693). CONCLUSIONS: Test-retest reliability for functional tasks utilized in the FPPE project was generally excellent across a sample of high school ATs, supporting the utility of these tasks in longitudinal assessments in secondary school settings. Supported by NIH Grant 5R01-AR062578-02.

Effects Of High-intensity Functional Circuit Training On Motor Function And Exercise Motivation

PURPOSE: Only a small share of the world population meets current physical activity guidelines, which recommend regular engagement in endurance, strength, and neuromotor exercise. As lack of time has been reported to constitute a major cause of inactivity, multidimensional methods with short training duration might be a promising alternative to classical, volume-oriented approaches. This randomized-controlled trial aimed to examine the effects of a high-intensity functional circuit (HIFCT) training program on motor function and motivation to exercise in healthy, untrained adults. METHODS: 25 inactive participants (26±5 yrs, 9♂) were randomly allocated to two groups. The intervention group (HIFCT, n=15) 3×/wk performed functional exercises incorporating complex whole-body movements (e.g. Squats, Step-Ups, Burpees) in a circuit format. The 15 min workouts were composed of repetitive 20s all-out bouts with 10s breaks. In the comparison group (moderate aerobic exercise, MAE) the participants walked 3×/wk for 50 min at moderate intensity (progressively increased from 50 to 60% of the individual heart rate reserve). Motor outcomes, measured prior to and after the six-week intervention, were cycling capacity (maximum work load), dynamic maximum strength (leg and shoulder press), postural control (force plate), and jump capacity (reactive strength index, counter-movement jump, single leg hop for distance). Motivation to exercise was assessed using the self-concordance index. Systematic group differences were detected with the Mann-Whitney-U-test (α=.05). RESULTS: In comparison to MAE, HIFCT increased maximum leg strength (difference of relative median pre-post changes between groups: 6%), shoulder strength (8.4%), and cycling workload (6.5%; p<.05). No differences were found for postural control and jump capacity (p>.05). Although not statistically significant, there was a tendency for increased self-concordance following HIFCT (p<.1) CONCLUSION: Despite considerably shorter training duration, HIFCT enhances motor function in healthy untrained adults more effectively than MAE. It might moreover be better suited to motivate inactive people to engage in regular activity. Further research should thus investigate long-term adherence to the program and its effectivity in other settings.