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Bell DR, Oates DC, Clark MA, Padua DA. Two- and 3-dimensional knee valgus are reduced after an exercise intervention in young adults with demonstrable valgus during squatting. J Athl Train 2013; 48:442-9. [PMID: 23724771 DOI: 10.4085/1062-6050-48.3.16] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Two-dimensional (or medial knee displacement [MKD]) and 3-dimensional (3D) knee valgus are theorized to contribute to anterior cruciate ligament injuries. However, whether these displacements can be improved in the double-legged squat (DLS) after an exercise intervention is unclear. OBJECTIVE To determine if MKD and 3D knee valgus are improved in a DLS after an exercise intervention. DESIGN Randomized controlled clinical trial. SETTING Research laboratory. PATIENTS OR OTHER PARTICIPANTS A total of 32 participants were enrolled in this study and were randomly assigned to the control (n = 16) or intervention (n = 16) group. During a DLS, all participants demonstrated knee valgus that was corrected with a heel lift. INTERVENTION(S) The intervention group completed 10 sessions of directed exercise that focused on hip and ankle strength and flexibility over a 2- to 3-week period. MAIN OUTCOME MEASURE(S) We assessed MKD and 3D knee valgus during the DLS using an electromagnetic tracking system. Hip strength and ankle-dorsiflexion range of motion were measured. Change scores were calculated for MKD and 3D valgus at 0%, 10%, 20%, 30%, 40%, and 50% phases, and group (2 levels)-by phase (6 levels) repeated-measures analyses of variance were conducted. Independent t tests were used to compare change scores in other variables (α < .05). RESULTS The MKD decreased from 20% to 50% of the DLS (P = .02) and 3D knee valgus improved from 30% to 50% of the squat phase (P = .001). Ankle-dorsiflexion range of motion (knee extended) increased in the intervention group (P = .009). No other significant findings were observed (P > .05). CONCLUSIONS The intervention reduced MKD and 3D knee valgus during a DLS. The intervention also increased ankle range of motion. Our inclusion criteria might have limited our ability to observe changes in hip strength.
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Padua DA, Bell DR, Clark MA. Neuromuscular characteristics of individuals displaying excessive medial knee displacement. J Athl Train 2013; 47:525-36. [PMID: 23068590 DOI: 10.4085/1062-6050-47.5.10] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Knee-valgus motion is a potential risk factor for certain lower extremity injuries, including anterior cruciate ligament injury and patellofemoral pain. Identifying neuromuscular characteristics associated with knee-valgus motion, such as hip and lower leg muscle activation, may improve our ability to prevent lower extremity injuries. OBJECTIVE We hypothesized that hip and lower leg muscle-activation amplitude would differ among individuals displaying knee valgus (medial knee displacement) during a double-legged squat compared with those who did not display knee valgus. We further suggested that the use of a heel lift would alter lower leg muscle activation and frontal-plane knee motion in those demonstrating medial knee displacement. DESIGN Descriptive laboratory study. SETTING Research laboratory. PATIENTS OR OTHER PARTICIPANTS A total of 37 healthy participants were assigned to the control (n = 19) or medial-knee-displacement (n = 18) group based on their double-legged squat performance. MAIN OUTCOME MEASURE(S) Muscle-activation amplitude for the gluteus maximus, gluteus medius, adductor magnus, medial and lateral gastrocnemius, and tibialis anterior was measured during 2 double-legged squat tasks. The first task consisted of performing a double-legged squat without a heel lift; the second consisted of performing a double-legged squat task with a 2-in (5.08-cm) lift under the heels. RESULTS Muscle-activation amplitude for the hip adductor, gastrocnemius, and tibialis anterior was greater in those who displayed knee valgus than in those who did not (P < .05). Also, use of heel lifts resulted in decreased activation of the gluteus maximus, hip adductor, gastrocnemius, and tibialis anterior muscles (P < .05). Use of heel lifts also eliminated medially directed frontal-plane knee motion in those displaying medial knee displacement. CONCLUSIONS Medial knee displacement during squatting tasks appears to be associated with increased hip-adductor activation and increased co-activation of the gastrocnemius and tibialis anterior muscles.
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Aragon VJ, Oyama S, Oliaro SM, Padua DA, Myers JB. Trunk-rotation flexibility in collegiate softball players with or without a history of shoulder or elbow injury. J Athl Train 2013; 47:507-13. [PMID: 23068587 DOI: 10.4085/1062-6050-47.3.11] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Throwing is a whole-body motion that requires the transfer of momentum from the lower extremity to the upper extremity via the trunk. No research to date examines the association between a history of shoulder or elbow injury and trunk flexibility in overhead athletes. OBJECTIVE To determine if injury history and trunk-rotation flexibility are associated and to compare trunk-rotation flexibility measured using 3 clinical tests: half-kneeling rotation test with the bar in the back, half-kneeling rotation test with the bar in the front, and seated rotation test in softball position players with or without a history of shoulder or elbow injury. DESIGN Cross-sectional design. SETTING University softball facilities. PATIENTS OR OTHER PARTICIPANTS Sixty-five female National Collegiate Athletic Association Division I softball position players. INTERVENTION(S) Trunk-rotation flexibility was measured with 3 clinical tests. Recent injury history was obtained using a questionnaire and verified by the certified athletic trainer. MAIN OUTCOME MEASURE(S) Binomial regression models were used to determine if injury history was associated with flexibility categories (high, normal, or limited tertiles) for each of the 6 (3 tests × 2 directions) trunk-rotation flexibility measures. Trunk-rotation flexibility measures from 3 clinical tests were compared between participants with and without a history of shoulder or elbow injury using analysis-of-variance models. RESULTS When measured using the half-kneeling rotation test with the bar in the back and the seated rotation test, injury history and forward trunk-rotation flexibility were associated. However, no mean group differences were seen in trunk-rotation flexibility between participants with and without a history of shoulder or elbow injury. CONCLUSIONS Limited forward trunk-rotation flexibility may be a risk factor for shoulder or elbow injuries. However, further study is needed to confirm the study finding.
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Shultz SJ, Schmitz RJ, Benjaminse A, Chaudhari AM, Collins M, Padua DA. ACL Research Retreat VI: an update on ACL injury risk and prevention. J Athl Train 2013; 47:591-603. [PMID: 23068597 DOI: 10.4085/1062-6050-47.5.13] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Joshi M, Thigpen CA, Bunn K, Karas SG, Padua DA. Shoulder external rotation fatigue and scapular muscle activation and kinematics in overhead athletes. J Athl Train 2013; 46:349-57. [PMID: 21944066 DOI: 10.4085/1062-6050-46.4.349] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Glenohumeral external rotation (GH ER) muscle fatigue might contribute to shoulder injuries in overhead athletes. Few researchers have examined the effect of such fatigue on scapular kinematics and muscle activation during a functional movement pattern. OBJECTIVE To examine the effects of GH ER muscle fatigue on upper trapezius, lower trapezius, serratus anterior, and infraspinatus muscle activation and to examine scapular kinematics during a diagonal movement task in overhead athletes. SETTING Human performance research laboratory. DESIGN Descriptive laboratory study. PATIENTS OR OTHER PARTICIPANTS Our study included 25 overhead athletes (15 men, 10 women; age = 20 ± 2 years, height = 180 ± 11 cm, mass = 80 ± 11 kg) without a history of shoulder pain on the dominant side. INTERVENTION(S) We tested the healthy, dominant shoulder through a diagonal movement task before and after a fatiguing exercise involving low-resistance, high-repetition, prone GH ER from 0° to 75° with the shoulder in 90° of abduction. MAIN OUTCOME MEASURE(S) Surface electromyography was used to measure muscle activity for the upper trapezius, lower trapezius, serratus anterior, and infraspinatus. An electromyographic motion analysis system was used to assess 3-dimensional scapular kinematics. Repeated-measures analyses of variance (phase × condition) were used to test for differences. RESULTS We found a decrease in ascending-phase and descending-phase lower trapezius activity (F(1,25) = 5.098, P = .03) and an increase in descending-phase infraspinatus activity (F(1,25) = 5.534, P = .03) after the fatigue protocol. We also found an increase in scapular upward rotation (F(1,24) = 3.7, P = .04) postfatigue. CONCLUSIONS The GH ER muscle fatigue protocol used in this study caused decreased lower trapezius and increased infraspinatus activation concurrent with increased scapular upward rotation range of motion during the functional task. This highlights the interdependence of scapular and glenohumeral force couples. Fatigue-induced alterations in the lower trapezius might predispose the infraspinatus to injury through chronically increased activation.
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Walsh M, Boling MC, McGrath M, Blackburn JT, Padua DA. Lower extremity muscle activation and knee flexion during a jump-landing task. J Athl Train 2013; 47:406-13. [PMID: 22889656 DOI: 10.4085/1062-6050-47.4.17] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Decreased sagittal-plane motion at the knee during dynamic tasks has been reported to increase impact forces during landing, potentially leading to knee injuries such as anterior cruciate ligament rupture. OBJECTIVE To describe the relationship between lower extremity muscle activity and knee-flexion angle during a jump-landing task. DESIGN Cross-sectional study. SETTING Research laboratory. PATIENTS OR OTHER PARTICIPANTS Thirty recreationally active volunteers (15 men, 15 women: age = 21.63 ± 2.01 years, height = 173.95 ± 11.88 cm, mass = 72.57 ± 14.25 kg). INTERVENTION(S) Knee-flexion angle and lower extremity muscle activity were collected during 10 trials of a jump-landing task. MAIN OUTCOME MEASURE(S) Simple correlation analyses were performed to determine the relationship between each knee-flexion variable (initial contact, peak, and displacement) and electromyographic amplitude of the gluteus maximus (GMAX), quadriceps (VMO and VL), hamstrings, gastrocnemius, and quadriceps : hamstring (Q : H) ratio. Separate forward stepwise multiple regressions were conducted to determine which combination of muscle activity variables predicted each knee-flexion variable. RESULTS During preactivation, VMO and GMAX activity and the Q : H ratio were negatively correlated with knee-flexion angle at initial contact (VMO: r = 0.382, P = .045; GMAX: r = 0.385, P = .043; Q : H ratio: r = 0.442, P = .018). The VMO, VL, and GMAX deceleration values were negatively correlated with peak knee-flexion angle (VMO: r = 0.687, P = .001; VL: r = 0.467, P = .011; GMAX: r = 0.386, P = .043). The VMO and VL deceleration values were negatively correlated with knee-flexion displacement (VMO: r = 0.631, P = .001; VL: r = 0.453, P = .014). The Q : H ratio and GM activity predicted 34.7% of the variance in knee-flexion angle at initial contact (P = .006). The VMO activity predicted 47.1% of the variance in peak knee-flexion angle (P = .001). The VMO and VL activity predicted 49.5% of the variance in knee-flexion displacement (P = .001). CONCLUSIONS Greater quadriceps and GMAX activation and less hamstrings and gastrocnemius activation were correlated with smaller knee-flexion angles. This landing strategy may predispose an individual to increased impact forces due to the negative influence on knee-flexion position.
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Begalle RL, Distefano LJ, Blackburn T, Padua DA. Quadriceps and hamstrings coactivation during common therapeutic exercises. J Athl Train 2013; 47:396-405. [PMID: 22889655 DOI: 10.4085/1062-6050-47.4.01] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
CONTEXT Anterior tibial shear force and knee valgus moment increase anterior cruciate ligament (ACL) loading. Muscle coactivation of the quadriceps and hamstrings influences anterior tibial shear force and knee valgus moment, thus potentially influencing ACL loading and injury risk. Therefore, identifying exercises that facilitate balanced activation of the quadriceps and hamstrings might be beneficial in ACL injury rehabilitation and prevention. OBJECTIVE To quantify and compare quadriceps with hamstrings coactivation electromyographic (EMG) ratios during commonly used closed kinetic chain exercises. DESIGN Cross-sectional study. SETTING Research laboratory. PATIENTS OR OTHER PARTICIPANTS Twenty-seven healthy, physically active volunteers (12 men, 15 women; age = 22.1 ± 3.1 years, height = 171.4 ± 10 cm, mass = 72.4 ± 16.7 kg). INTERVENTION(S) Participants completed 9 separate closed chain therapeutic exercises in a randomized order. MAIN OUTCOME MEASURE(S) Surface electromyography quantified the activity level of the vastus medialis (VM), vastus lateralis (VL), medial hamstrings (MH), and biceps femoris (BF) muscles. The quadriceps-to-hamstrings (Q:H) coactivation ratio was computed as the sum of average quadriceps (VM, VL) EMG amplitude divided by the sum of average hamstrings (MH, BF) EMG amplitude for each trial. We used repeated-measures analyses of variance to compare Q:H ratios and individual muscle contributions across exercises (α = .05), then used post hoc Tukey analyses. RESULTS We observed a main effect for exercise (F(3,79) = 22.6, P< .001). The post hoc Tukey analyses revealed smaller Q:H ratios during the single-limb dead lift (2.87 ± 1.77) than the single-limb squat (5.52 ± 2.89) exercise. The largest Q:H ratios were observed during the transverse-lunge (7.78 ± 5.51, P< .001), lateral-lunge (9.30 ± 5.53, P< .001), and forward-lunge (9.70 ± 5.90, P< .001) exercises. CONCLUSIONS The most balanced (smallest) coactivation ratios were observed during the single-limb dead-lift, lateral-hop, transverse-hop, and lateral band-walk exercises. These exercises potentially could facilitate balanced activation in ACL rehabilitation and injury-prevention programs. They also could be used in postinjury rehabilitation programs in a safe and progressive manner.
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Brown CN, Padua DA, Marshall SW, Guskiewicz KM. Hip kinematics during a stop-jump task in patients with chronic ankle instability. J Athl Train 2013; 46:461-7. [PMID: 22488131 DOI: 10.4085/1062-6050-46.5.461] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
CONTEXT Chronic ankle instability (CAI) commonly develops after lateral ankle sprain. Movement pattern differences at proximal joints may play a role in instability. OBJECTIVE To determine whether people with mechanical ankle instability (MAI) or functional ankle instability (FAI) exhibited different hip kinematics and kinetics during a stop-jump task compared with "copers." DESIGN Cross-sectional study. SETTING Sports medicine research laboratory. PATIENTS OR OTHER PARTICIPANTS Sixty-three recreational athletes, 21 (11 men, 10 women) per group, matched for sex, age, height, mass, and limb dominance. All participants reported a history of a moderate to severe ankle sprain. The participants with MAI and FAI reported 2 or more episodes of giving way at the ankle in the last year and decreased functional ability; copers did not. The MAI group demonstrated clinically positive anterior drawer and talar tilt tests, whereas the FAI group and copers did not. INTERVENTION(S) Participants performed a maximum-speed approach run and a 2-legged stop jump followed by a maximum vertical jump. MAIN OUTCOME MEASURE(S) An electromagnetic tracking device synchronized with a force plate collected data during the stance phase of a 2-legged stop jump. Hip motion was measured from initial contact to takeoff into the vertical jump. Group differences in hip kinematics and kinetics were assessed. RESULTS The MAI group demonstrated greater hip flexion at initial contact and at maximum (P = .029 and P = .017, respectively) and greater hip external rotation at maximum (P = .035) than the coper group. The MAI group also demonstrated greater hip flexion displacement than both the FAI (P = .050) and coper groups (P = .006). No differences were noted between the FAI and coper groups in hip kinematic variables or among any of the groups in ground reaction force variables. CONCLUSIONS The MAI group demonstrated different hip kinematics than the FAI and coper groups. Proximal joint motion may be affected by ankle joint function and laxity, and clinicians may need to assess proximal joints after repeated ankle sprains.
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Padua DA, Distefano LJ. Sagittal Plane Knee Biomechanics and Vertical Ground Reaction Forces Are Modified Following ACL Injury Prevention Programs: A Systematic Review. Sports Health 2012; 1:165-73. [PMID: 23015868 PMCID: PMC3445071 DOI: 10.1177/1941738108330971] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Context: Injuries to the anterior cruciate ligament (ACL) occur because of excessive loading on the knee. ACL injury prevention programs can influence sagittal plane ACL loading factors and vertical ground reaction force (VGRF). Objective: To determine the influence of ACL injury prevention programs on sagittal plane knee biomechanics (anterior tibial shear force, knee flexion angle/moments) and VGRF. Data Sources: The PubMed database was searched for studies published between January 1988 and June 2008. Reference lists of selected articles were also reviewed. Study Selection: Studies were included that evaluated healthy participants for knee flexion angle, sagittal plane knee kinetics, or VGRF after performing a multisession training program. Two individuals reviewed all articles and determined which articles met the selection criteria. Approximately 4% of the articles fulfilled the selection criteria. Data Extraction: Data were extracted regarding each program’s duration, frequency, exercise type, population, supervision, and testing procedures. Means and variability measures were recorded to calculate effect sizes. One reviewer extracted all data and assessed study quality using PEDro (Physiotherapy Evidence Database). A second reviewer (blinded) verified all information. Results: There is moderate evidence to indicate that knee flexion angle, external knee flexion moment, and VGRF can be successfully modified by an ACL injury prevention program. Programs utilizing multiple exercises (ie, integrated training) appear to produce the most improvement, in comparison to that of single-exercise programs. Knee flexion angle was improved following integrated training (combined balance and strength exercises or combined plyometric and strength exercises). Similarly, external knee flexion moment was improved following integrated training consisting of balance, plyometric, and strength exercises. VGRF was improved when incorporating supervision with instruction and feedback on proper technique. Conclusion: ACL injury prevention programs that are aimed at modifying sagittal plane knee biomechanics and VGRF should use an integrated training approach that incorporates instruction and feedback on proper movement technique.
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Abstract
Context: The Balance Error Scoring System (BESS) is commonly used by researchers and clinicians to evaluate balance.A growing number of studies are using the BESS as an outcome measure beyond the scope of its original purpose. Objective: To provide an objective systematic review of the reliability and validity of the BESS. Data Sources: PubMed and CINHAL were searched using Balance Error Scoring System from January 1999 through December 2010. Study Selection: Selection was based on establishment of the reliability and validity of the BESS. Research articles were selected if they established reliability or validity (criterion related or construct) of the BESS, were written in English, and used the BESS as an outcome measure. Abstracts were not considered. Results: Reliability of the total BESS score and individual stances ranged from poor to moderate to good, depending on the type of reliability assessed. The BESS has criterion-related validity with force plate measures; more difficult stances have higher agreement than do easier ones. The BESS is valid to detect balance deficits where large differences exist (concussion or fatigue). It may not be valid when differences are more subtle. Conclusions: Overall, the BESS has moderate to good reliability to assess static balance. Low levels of reliability have been reported by some authors. The BESS correlates with other measures of balance using testing devices. The BESS can detect balance deficits in participants with concussion and fatigue. BESS scores increase with age and with ankle instability and external ankle bracing. BESS scores improve after training.
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Aguilar AJ, DiStefano LJ, Brown CN, Herman DC, Guskiewicz KM, Padua DA. A dynamic warm-up model increases quadriceps strength and hamstring flexibility. J Strength Cond Res 2012; 26:1130-41. [PMID: 22446678 DOI: 10.1519/jsc.0b013e31822e58b6] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Research suggests that static stretching can negatively influence muscle strength and power and may result in decreased functional performance. The dynamic warm-up (DWU) is a common alternative to static stretching before physical activity, but there is limited research investigating the effects of a DWU. The purpose of this study was to compare the acute effects of a DWU and static stretching warm-up (SWU) on muscle flexibility, strength, and vertical jump using a randomized controlled trial design. Forty-five volunteers were randomly assigned into a control (CON), SWU, or DWU group. All participants rode a stationary bicycle for 5 minutes and completed a 10-minute warm-up protocol. During this protocol, the DWU group performed dynamic stretching and running, the SWU group performed static stretching, and the CON group rested. Dependent variables were measured immediately before and after the warm-up protocol. A digital inclinometer measured flexibility (degrees) for the hamstrings, quadriceps, and hip flexor muscles. An isokinetic dynamometer measured concentric and eccentric peak torque (N·m/kg) for the hamstrings and quadriceps. A force plate was used to measure vertical jump height (meters) and power (watts). In the DWU group, there was a significant increase in hamstring flexibility (pretest: 26.4 ± 13.5°, posttest: 16.9 ± 9.4°; p < .0001) and eccentric quadriceps peak torque (pretest: 2.49 ± 0.83 N·m/kg, posttest: 2.78 ± 0.69 N·m/kg; p = 0.04). The CON and SWU did not significantly affect any flexibility, strength, or vertical jump measures (p > 0.05). The DWU significantly improved eccentric quadriceps strength and hamstrings flexibility, whereas the SWU did not facilitate any positive or negative changes in muscle flexibility, strength, power, or vertical jump. Therefore, the DWU may be a better preactivity warm-up choice than an SWU.
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Bell DR, Vesci BJ, DiStefano LJ, Guskiewicz KM, Hirth CJ, Padua DA. Muscle Activity and Flexibility in Individuals With Medial Knee Displacement During the Overhead Squat. ACTA ACUST UNITED AC 2012. [DOI: 10.3928/19425864-20110817-03] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Padua DA, DiStefano LJ, Marshall SW, Beutler AI, de la Motte SJ, DiStefano MJ. Retention of movement pattern changes after a lower extremity injury prevention program is affected by program duration. Am J Sports Med 2012; 40:300-6. [PMID: 22064608 DOI: 10.1177/0363546511425474] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Changes in movement patterns have been repeatedly observed immediately after completing a lower extremity injury prevention program. However, it is not known if movement pattern changes are maintained after discontinuing the training program. HYPOTHESIS The ability to maintain movement pattern changes after training has ceased may be influenced by the program's duration. The authors hypothesized that among individuals who completed either a 3-month or 9-month training program and who demonstrated immediate movement pattern changes, only those who completed the 9-month training program would maintain movement pattern changes after a 3-month period of no longer performing the exercises. STUDY DESIGN Cohort study; Level of evidence, 2. METHODS A total of 140 youth soccer athletes from 15 separate teams volunteered to participate. Athletes' movement patterns were assessed using the Landing Error Scoring System (LESS) at pretest, posttest, and 3 months after ceasing the program (retention test). Eighty-four of the original 140 participants demonstrated improvements in their LESS scores between pretest and posttest (change in LESS score >0) and were included in the final analyses for this study (n = 84; 20 boys and 64 girls; mean age, 14 ± 2 years; age range, 11-17 years). Teams performed 3-month (short-duration group) and 9-month (extended-duration group) injury prevention programs. The exercises performed were identical for both groups. Teams performed the programs as part of their normal warm-up routine. RESULTS Although both groups improved their total LESS scores from pretest to posttest, only the extended-duration training group retained their improvements 3 months after ceasing the injury prevention program (F(2,137) = 3.38; P = .04). CONCLUSION Results suggest that training duration may be an important factor to consider when designing injury prevention programs that facilitate long-term changes in movement control.
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Bell DR, Blackburn JT, Norcross MF, Ondrak KS, Hudson JD, Hackney AC, Padua DA. Estrogen and muscle stiffness have a negative relationship in females. Knee Surg Sports Traumatol Arthrosc 2012; 20:361-7. [PMID: 21695466 DOI: 10.1007/s00167-011-1577-y] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Accepted: 06/09/2011] [Indexed: 10/18/2022]
Abstract
PURPOSE Hormonal fluctuations are one potential reason why females might have a greater rate of noncontact ACL injury. The hamstrings are capable of limiting anterior cruciate ligament (ACL) loading. This study examined whether relationships existed between reproductive hormones (estradiol-β-17, free testosterone, and progesterone) and hamstring neuromechanical variables (hamstring musculotendinous stiffness (MTS), rate of force production (RFP), time to 50% peak torque (T50%), and electromechanical delay (EMD)) in genders combined and independently. METHODS Muscle properties of the hamstrings and reproductive hormones were evaluated in 30 subjects (15 males and 15 females) that were free from lower extremity injury and had no history of ACL injury. Females were tested 3-5 days after the onset of menses and were not using oral contraceptive. Pearson correlation coefficients were calculated for each hormone and muscle property. RESULTS For genders combined, estrogen (mean = 46.0 ± 28.2 pg/mL) was negatively correlated with RFP (mean = 758.8 ± 507.6 N/kg s(-1), r = -0.43, P = 0.02) and MTS (mean = 12.8 ± 2.6 N/cm, r = -0.43, P = 0.02). Free testosterone (mean = 13.2 ± 13.0 pg/mL) was positively correlated with RFP (r = 0.56, P < 0.01) and MTS (r = 0.46, P = 0.01) but negatively correlated with T50% (mean = 114.7 ± 38.9 ms, r = -0.43, P = 0.02). When gender was considered separately, females demonstrated negative correlation between estrogen (mean = 68.0 ± 23.2 pg/mL) and MTS (mean = 11.7 ± 1.5 N/cm, r = -0.53, P = 0.05) and free testosterone (mean = 1.5 ± 0.6 pg/mL) and MTS (r = -0.52, P = 0.05). Males alone displayed no significant correlations between the selected hormones and muscle properties. CONCLUSIONS Correlations exist between muscle properties and reproductive hormones. Females, however, may be more sensitive to reproductive hormones and their fluctuations.
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Rondeau MW, Padua DA, Thigpen CA, Harrington SE. Precision and Validity of a Clinical Method for Pectoral Minor Length Assessment in Overhead-Throwing Athletes. ACTA ACUST UNITED AC 2012. [DOI: 10.3928/19425864-20110630-01] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Brown CN, Padua DA, Marshall SW, Guskiewicz KM. Authors' Reply. J Athl Train 2011. [DOI: 10.4085/1062-6050-46.5.469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Padua DA. Executing a collaborative prospective risk-factor study: findings, successes, and challenges. J Athl Train 2011; 45:519-21. [PMID: 20831402 DOI: 10.4085/1062-6050-45.5.519] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Shultz SJ, Schmitz RJ, Nguyen AD, Chaudhari AM, Padua DA, McLean SG, Sigward SM. ACL Research Retreat V: an update on ACL injury risk and prevention, March 25-27, 2010, Greensboro, NC. J Athl Train 2011; 45:499-508. [PMID: 20831398 DOI: 10.4085/1062-6050-45.5.499] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Frank BS, Goerger BM, Bell DR, Norcross MF, Padua DA, Blackburn T. Trunk Neuromuscular Control is Associated with ACL Loading Mechanisms During an Athletic Cutting Task. Med Sci Sports Exerc 2011. [DOI: 10.1249/01.mss.0000402244.76775.52] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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de la Motte SJ, Beutler AI, Padua DA, DiStefano LJ, Marshall SW. Results of an Injury Prevention Training Program in Cadets Vary Based on Level of Supervision. Med Sci Sports Exerc 2011. [DOI: 10.1249/01.mss.0000401175.18167.d3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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DiStefano LJ, Blackburn JT, Marshall SW, Guskiewicz KM, Garrett WE, Padua DA. Effects of an age-specific anterior cruciate ligament injury prevention program on lower extremity biomechanics in children. Am J Sports Med 2011; 39:949-57. [PMID: 21285445 DOI: 10.1177/0363546510392015] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Implementing an anterior cruciate ligament injury prevention program to athletes before the age at which the greatest injury risk occurs (15-17 years) is important from a prevention standpoint. However, it is unknown whether standard programs can modify lower extremity biomechanics in pediatric populations or if specialized training is required. HYPOTHESIS/PURPOSE To compare the effects of traditional and age-specific pediatric anterior cruciate ligament injury prevention programs on lower extremity biomechanics during a cutting task in youth athletes. The authors hypothesized that the age-specific pediatric program would result in greater sagittal plane motion (ie, hip and knee flexion) and less motion in the transverse and frontal plane (ie, knee valgus, knee and hip rotation) as compared with the traditional program. STUDY DESIGN Randomized controlled trial; Level of evidence, 1. METHODS Sixty-five youth soccer athletes (38 boys, 27 girls) volunteered to participate. The mean age of participants was 10 ± 1 years. Teams (n, 7) were cluster randomized to a pediatric injury prevention program, a traditional injury prevention program, or a control group. The pediatric program was modified from the traditional program to include more feedback, progressions, and variety. Teams performed their programs as part of their normal warm-up routine. Three-dimensional lower extremity biomechanics were assessed during a sidestep cutting task before and after completion of the 9-week intervention period. RESULTS The pediatric program reduced the amount of knee external rotation at initial ground contact during the cutting task, F ((2,62)) = 3.79, P = .03 (change: pediatric, 7.73° ± 10.71°; control, -0.35° ± 7.76°), as compared with the control group after the intervention period. No other changes were observed. CONCLUSION The injury prevention program designed for a pediatric population modified only knee rotation during the cutting task, whereas the traditional program did not result in any changes in cutting biomechanics. These findings suggest limited effectiveness of both programs for athletes younger than 12 years of age in terms of biomechanics during a cutting task.
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Zinder SM, Padua DA, Mihalik JP, Guskiewicz KM. Sex Differences on Postural Sway Across Three Ankle Bracing Conditions. Med Sci Sports Exerc 2011. [DOI: 10.1249/01.mss.0000401446.09730.f9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Goto S, Bell DR, Padua DA. Association of Gluteus Medius Activation with Leg Muscle Activation and Flexibility. Med Sci Sports Exerc 2011. [DOI: 10.1249/01.mss.0000402579.19466.5c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Bell DR, Blackburn JT, Hackney AC, Marshall SW, Beutler AI, Padua DA. Hamstring Stiffness and Knee Laxity Across the Menstrual Cycle in Females with ACL Reconstruction. Med Sci Sports Exerc 2011. [DOI: 10.1249/01.mss.0000402240.23410.ff] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Padua DA, DiStefano LJ, DiStefano M, Beutler AI, Marshall SW. Duration of Training affects Retention of Movement Pattern Changes Following an ACL Injury Prevention Program. Med Sci Sports Exerc 2011. [DOI: 10.1249/01.mss.0000402711.36978.66] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Goerger BM, Frank BS, Cavanaugh JT, Bell DR, Padua DA. Gender Differences in Postural Control During Unstable Sitting. Med Sci Sports Exerc 2011. [DOI: 10.1249/01.mss.0000401464.08837.c3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Fong CM, Blackburn JT, Norcross MF, McGrath M, Padua DA. Ankle-dorsiflexion range of motion and landing biomechanics. J Athl Train 2011; 46:5-10. [PMID: 21214345 DOI: 10.4085/1062-6050-46.1.5] [Citation(s) in RCA: 189] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT A smaller amount of ankle-dorsiflexion displacement during landing is associated with less knee-flexion displacement and greater ground reaction forces, and greater ground reaction forces are associated with greater knee-valgus displacement. Additionally, restricted dorsiflexion range of motion (ROM) is associated with greater knee-valgus displacement during landing and squatting tasks. Because large ground reaction forces and valgus displacement and limited knee-flexion displacement during landing are anterior cruciate ligament (ACL) injury risk factors, dorsiflexion ROM restrictions may be associated with a greater risk of ACL injury. However, it is unclear whether clinical measures of dorsiflexion ROM are associated with landing biomechanics. OBJECTIVE To evaluate relationships between dorsiflexion ROM and landing biomechanics. DESIGN Descriptive laboratory study. SETTING Research laboratory. PATIENTS OR OTHER PARTICIPANTS Thirty-five healthy, physically active volunteers. INTERVENTION(S) Passive dorsiflexion ROM was assessed under extended-knee and flexed-knee conditions. Landing biomechanics were assessed via an optical motion-capture system interfaced with a force plate. MAIN OUTCOME MEASURE(S) Dorsiflexion ROM was measured in degrees using goniometry. Knee-flexion and knee-valgus displacements and vertical and posterior ground reaction forces were calculated during the landing task. Simple correlations were used to evaluate relationships between dorsiflexion ROM and each biomechanical variable. RESULTS Significant correlations were noted between extended-knee dorsiflexion ROM and knee-flexion displacement (r = 0.464, P = .029) and vertical (r = -0.411, P = .014) and posterior (r = -0.412, P = .014) ground reaction forces. All correlations for flexed-knee dorsiflexion ROM and knee-valgus displacement were nonsignificant. CONCLUSIONS Greater dorsiflexion ROM was associated with greater knee-flexion displacement and smaller ground reaction forces during landing, thus inducing a landing posture consistent with reduced ACL injury risk and limiting the forces the lower extremity must absorb. These findings suggest that clinical techniques to increase plantar-flexor extensibility and dorsiflexion ROM may be important additions to ACL injury-prevention programs.
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Thigpen CA, Padua DA, Michener LA, Guskiewicz K, Giuliani C, Keener JD, Stergiou N. Head and shoulder posture affect scapular mechanics and muscle activity in overhead tasks. J Electromyogr Kinesiol 2010; 20:701-9. [DOI: 10.1016/j.jelekin.2009.12.003] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2009] [Revised: 10/20/2009] [Accepted: 12/14/2009] [Indexed: 11/25/2022] Open
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DiStefano LJ, Padua DA, Blackburn JT, Garrett WE, Guskiewicz KM, Marshall SW. Integrated injury prevention program improves balance and vertical jump height in children. J Strength Cond Res 2010; 24:332-42. [PMID: 20072067 DOI: 10.1519/jsc.0b013e3181cc2225] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Implementing an injury prevention program to athletes under age 12 years may reduce injury rates. There is limited knowledge regarding whether these young athletes will be able to modify balance and performance measures after completing a traditional program that has been effective with older athletes or whether they require a specialized program for their age. The purpose of this study was to compare the effects of a pediatric program, which was designed specifically for young athletes, and a traditional program with no program in the ability to change balance and performance measures in youth athletes. We used a cluster-randomized controlled trial to evaluate the effects of the programs before and after a 9-week intervention period. Sixty-five youth soccer athletes (males: n = 37 mass = 34.16 +/- 5.36 kg, height = 143.07 +/- 6.27 cm, age = 10 +/- 1 yr; females: n = 28 mass = 33.82 +/- 5.37 kg, height = 141.02 +/- 6.59 cm) volunteered to participate and attended 2 testing sessions in a research laboratory. Teams were cluster-randomized to either a pediatric or traditional injury prevention program or a control group. Change scores for anterior-posterior and medial-lateral time-to-stabilization measures and maximum vertical jump height and power were calculated from pretest and post-test sessions. Contrary with our original hypotheses, the traditional program resulted in positive changes, whereas the pediatric program did not result in any improvements. Anterior-posterior time-to-stabilization decreased after the traditional program (mean change +/- SD = -0.92 +/- 0.49 s) compared with the control group (-0.49 +/- 0.59 s) (p = 0.003). The traditional program also increased vertical jump height (1.70 +/- 2.80 cm) compared with the control group (0.20 +/- 0.20 cm) (p = 0.04). There were no significant differences between control and pediatric programs. Youth athletes can improve balance ability and vertical jump height after completing an injury prevention program. Training specificity appears to affect improvements and should be considered with future program design.
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Goerger BM, Padua DA. Measures of Trunk Muscle Endurance and Neuromuscular Control Are Not Correlated. Med Sci Sports Exerc 2010. [DOI: 10.1249/01.mss.0000385452.89016.a3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Bell DR, Blackburn T, Norcross MF, Padua DA. There is no Relationship between Lower Extremity and Knee Flexor Stiffness. Med Sci Sports Exerc 2010. [DOI: 10.1249/01.mss.0000384754.78803.ac] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Norcross MF, Blackburn JT, Goerger BM, Padua DA. Lower Extremity Energy Absorption During Landing in Subjects with Different Peak Impact Forces. Med Sci Sports Exerc 2010. [DOI: 10.1249/01.mss.0000386409.02991.91] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Padua DA, DiStefano MJ, Clark MA. Comparison of Isolated and Integrated Training on Functional Performance Measures. Med Sci Sports Exerc 2010. [DOI: 10.1249/01.mss.0000385221.42441.af] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Oates DC, Bell DR, DiStefano LJ, Bensman MM, Padua DA. Relationship between Hip Muscle Co-Activation on Knee Valgus Moment During a Jump-Landing Task. Med Sci Sports Exerc 2010. [DOI: 10.1249/01.mss.0000384755.86426.f4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Boling MC, Padua DA, Alexander Creighton R. Concentric and eccentric torque of the hip musculature in individuals with and without patellofemoral pain. J Athl Train 2010; 44:7-13. [PMID: 19180213 DOI: 10.4085/1062-6050-44.1.7] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Individuals suffering from patellofemoral pain have previously been reported to have decreased isometric strength of the hip musculature; however, no researchers have investigated concentric and eccentric torque of the hip musculature in individuals with patellofemoral pain. OBJECTIVE To compare concentric and eccentric torque of the hip musculature in individuals with and without patellofemoral pain. DESIGN Case control. SETTING Research laboratory. PATIENTS OR OTHER PARTICIPANTS Twenty participants with patellofemoral pain (age = 26.8 +/- 4.5 years, height = 171.8 +/- 8.4 cm, mass = 72.4 +/- 16.8 kg) and 20 control participants (age = 25.6 +/- 2.8 years, height = 169.5 +/- 8.9 cm, mass = 70.0 +/- 16.9 kg) were tested. Volunteers with patellofemoral pain met the following criteria: knee pain greater than or equal to 3 cm on a 10-cm visual analog scale, insidious onset of symptoms not related to trauma, pain with palpation of the patellar facets, and knee pain during 2 of the following activities: stair climbing, jumping or running, squatting, kneeling, or prolonged sitting. Control participants were excluded if they had a prior history of patellofemoral pain, knee surgery in the past 2 years, or current lower extremity injury that limited participation in physical activity. INTERVENTION(S) Concentric and eccentric torque of the hip musculature was measured on an isokinetic dynamometer. All volunteers performed 5 repetitions of each strength test. Separate multivariate analyses of variance were performed to compare concentric and eccentric torque of the hip extensors, abductors, and external rotators between groups. MAIN OUTCOME MEASURE(S) Average and peak concentric and eccentric torque of the hip extensors, abductors, and external rotators. Torque measures were normalized to the participant's body weight multiplied by height. RESULTS The patellofemoral pain group was weaker than the control group for peak eccentric hip abduction torque (F(1,38) = 6.630, P = .014), and average concentric (F(1,38) = 4.156, P = .048) and eccentric (F(1,38) = 4.963, P = .032) hip external rotation torque. CONCLUSIONS The patellofemoral pain group displayed weakness in eccentric hip abduction and hip external rotation, which may allow for increased hip adduction and internal rotation during functional movements.
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Wilderman DR, Ross SE, Padua DA. Thigh muscle activity, knee motion, and impact force during side-step pivoting in agility-trained female basketball players. J Athl Train 2010; 44:14-25. [PMID: 19180214 DOI: 10.4085/1062-6050-44.1.14] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Improving neuromuscular control of hamstrings muscles might have implications for decreasing anterior cruciate ligament injuries in females. OBJECTIVE To examine the effects of a 6-week agility training program on quadriceps and hamstrings muscle activation, knee flexion angles, and peak vertical ground reaction force. DESIGN Prospective, randomized clinical research trial. SETTING Sports medicine research laboratory. PATIENTS OR OTHER PARTICIPANTS Thirty female intramural basketball players with no history of knee injury (age = 21.07 +/- 2.82 years, height = 171.27 +/- 4.66 cm, mass = 66.36 +/- 7.41 kg). INTERVENTION(S) Participants were assigned to an agility training group or a control group that did not participate in agility training. Participants in the agility training group trained 4 times per week for 6 weeks. MAIN OUTCOME MEASURE(S) We used surface electromyography to assess muscle activation for the rectus femoris, vastus medialis oblique, medial hamstrings, and lateral hamstrings for 50 milliseconds before initial ground contact and while the foot was in contact with the ground during a side-step pivot maneuver. Knee flexion angles (at initial ground contact, maximum knee flexion, knee flexion displacement) and peak vertical ground reaction force also were assessed during this maneuver. RESULTS Participants in the training group increased medial hamstrings activation during ground contact after the 6-week agility training program. Both groups decreased their vastus medialis oblique muscle activation during ground contact. Knee flexion angles and peak vertical ground reaction force did not change for either group. CONCLUSIONS Agility training improved medial hamstrings activity in female intramural basketball players during a side-step pivot maneuver. Agility training that improves hamstrings activity might have implications for reducing anterior cruciate ligament sprain injury associated with side-step pivots.
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DiStefano LJ, Clark MA, Padua DA. Evidence Supporting Balance Training in Healthy Individuals: A Systemic Review. J Strength Cond Res 2009; 23:2718-31. [DOI: 10.1519/jsc.0b013e3181c1f7c5] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Boling MC, Padua DA, Marshall SW, Guskiewicz K, Pyne S, Beutler A. A prospective investigation of biomechanical risk factors for patellofemoral pain syndrome: the Joint Undertaking to Monitor and Prevent ACL Injury (JUMP-ACL) cohort. Am J Sports Med 2009; 37:2108-16. [PMID: 19797162 PMCID: PMC2860575 DOI: 10.1177/0363546509337934] [Citation(s) in RCA: 300] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Patellofemoral pain syndrome is one of the most common chronic knee injuries; however, little research has been done to determine the risk factors for this injury. HYPOTHESIS Altered lower extremity kinematics and kinetics, decreased strength, and altered postural measurements will be risk factors. STUDY DESIGN Cohort study (prognosis); Level of evidence, 2. METHODS A total of 1597 participants were enrolled in this investigation and prospectively followed from the date of their enrollment (July 2005, July 2006, or July 2007) through January 2008, a maximum of 2.5 years of follow-up. Each participant underwent baseline data collection during their pre-freshman summer at the United States Naval Academy. Baseline data collection included 3-dimensional motion analysis during a jump-landing task, 6 lower extremity isometric strength tests, and postural alignment measurements (navicular drop and Q angle). RESULTS Risk factors for the development of patellofemoral pain syndrome included decreased knee flexion angle, decreased vertical ground-reaction force, and increased hip internal rotation angle during the jump-landing task. Additionally, decreased quadriceps and hamstring strength, increased hip external rotator strength, and increased navicular drop were risk factors for the development of patellofemoral pain syndrome. CONCLUSION Multiple modifiable risk factors for patellofemoral pain syndrome pain have been identified in this investigation. To decrease the incidence of this chronic injury, the risk factors for patellofemoral pain syndrome need to be targeted in injury prevention programs. CLINICAL RELEVANCE Prevention programs should focus on increasing strength of the lower extremity musculature along with instructing proper mechanics during dynamic movements to decrease the incidence of patellofemoral pain syndrome.
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Brown CN, Padua DA, Marshall SW, Guskiewicz KM. Variability of motion in individuals with mechanical or functional ankle instability during a stop jump maneuver. Clin Biomech (Bristol, Avon) 2009; 24:762-8. [PMID: 19679381 DOI: 10.1016/j.clinbiomech.2009.07.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2008] [Revised: 06/28/2009] [Accepted: 07/01/2009] [Indexed: 02/07/2023]
Abstract
BACKGROUND Movement variability may influence episodes of instability following lateral ankle sprain. METHODS Sixty-three recreational athletes with a history of moderate-severe ankle sprain were recruited. Mechanically and functionally unstable ankle groups had 2 episodes of instability in the last year. Mechanically unstable had clinically lax lateral ankle ligaments; functionally unstable and copers did not. Copers had a history of sprain but no residual instability. Lower extremity 3-dimensional kinematics and ground reaction forces were measured during a 2-legged stop jump. Average ensemble curves of eight trials normalized to 100% of stance phase were created. The coefficient of variation and average standard deviation of the ensemble curves of each variable were identified. A log(e) (ln) transformation was performed on the data. One-way ANOVAs with Tukey post hoc testing were utilized with alpha=0.05. FINDINGS The functionally unstable group demonstrated greater mean (standard deviation) ln coefficient of variation ankle inversion/eversion 3.56 (1.19) than the mechanically unstable 2.77 (0.95) and copers 2.74 (1.05) (P=0.05 and P=0.04; eta(p)(2)=0.12), and greater ln standard deviation ankle inversion/eversion 1.07 (0.78) than copers 0.61 (0.31) (eta(p)(2)=0.13). The mechanically unstable group demonstrated greater ln coefficient of variation anterior-posterior ground reaction force 3.69 (0.27) than functionally unstable 3.43 (0.25) (P=0.02; eta(p)(2)=0.13). INTERPRETATION Functionally unstable individuals demonstrated greater ankle frontal plane movement variability during a stop jump, which may increase risk of instability. Mechanically unstable participants demonstrated greater anterior-posterior ground reaction force variability, which may indicate difficulty mitigating landing forces with lax ligaments. Movement variability may influence episodes of ankle instability.
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Padua DA, Marshall SW, Boling MC, Thigpen CA, Garrett WE, Beutler AI. The Landing Error Scoring System (LESS) Is a valid and reliable clinical assessment tool of jump-landing biomechanics: The JUMP-ACL study. Am J Sports Med 2009; 37:1996-2002. [PMID: 19726623 DOI: 10.1177/0363546509343200] [Citation(s) in RCA: 357] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Anterior cruciate ligament injuries are common in athletes and have serious sequelae. A valid clinical tool that reliably identifies individuals at an increased risk for ACL injury would be highly useful for screening sports teams, because individuals identified as "high-risk" could then be provided with intensive prevention programs. HYPOTHESIS A clinical screening tool (the Landing Error Scoring System, or LESS) will reliably identify subjects with potentially high-risk biomechanics. STUDY DESIGN Cohort study (Diagnosis); Level of evidence, 2. METHODS A jump-landing-rebound task was used. Off-the-shelf camcorders recorded frontal and sagittal plane views of the subject performing the task. The LESS was scored from replay of this video. Three-dimensional lower extremity kinematics and kinetics were also collected and used as the gold standard against which the validity of the LESS was assessed. Three trials of the jump-landing task were collected for 2691 subjects. Kinematic and kinetic measures were compared across LESS score quartiles using 1-way analysis of variance; LESS quartiles were compared across genders using the chi-square test. The LESS scores from a subset of 50 subjects were rescored to determine intrarater and interrater reliability. RESULTS Subjects with high LESS scores (poor jump-landing technique) displayed significantly different lower extremity kinematics and kinetics compared with subjects with low LESS scores (excellent jump-landing technique). Women had higher (worse) LESS scores than men. Intrarater and interrater reliability of the LESS ranged from good to excellent. CONCLUSION The LESS is a valid and reliable tool for identifying potentially high-risk movement patterns during a jump-landing task.
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Blackburn JT, Padua DA. Sagittal-plane trunk position, landing forces, and quadriceps electromyographic activity. J Athl Train 2009; 44:174-9. [PMID: 19295962 DOI: 10.4085/1062-6050-44.2.174] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Researchers have suggested that large landing forces, excessive quadriceps activity, and an erect posture during landing are risk factors for anterior cruciate ligament (ACL) injury. The influence of knee kinematics on these risk factors has been investigated extensively, but trunk positioning has received little attention. OBJECTIVE To determine the effect of trunk flexion on landing forces and quadriceps activation during landing. DESIGN Two (sex) x 2 (task) repeated-measures design. SETTING Research laboratory. PATIENTS OR OTHER PARTICIPANTS Forty healthy, physically active volunteers (20 men, 20 women). INTERVENTION(S) Participants performed 2 drop-landing tasks. The first task represented the natural, or preferred, landing strategy. The second task was identical to the first except that participants flexed the trunk during landing. MAIN OUTCOME MEASURE(S) We measured peak vertical and posterior ground reaction forces and mean quadriceps electromyographic amplitude during the loading phase of landing (ie, the interval from initial ground contact to peak knee flexion). RESULTS Trunk flexion decreased the vertical ground reaction force (P < .001) and quadriceps electromyographic amplitude (P < .001). The effect of trunk flexion did not differ across sex for landing forces or quadriceps electromyographic activity. CONCLUSIONS We found that trunk flexion during landing reduced landing forces and quadriceps activity, thus potentially reducing the force imparted to the ACL. Research has indicated that trunk flexion during landing also increases knee and hip flexion, resulting in a less erect landing posture. In combination, these findings support emphasis on trunk flexion during landing as part of ACL injury-prevention programs.
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Herman DC, Oñate JA, Weinhold PS, Guskiewicz KM, Garrett WE, Yu B, Padua DA. The effects of feedback with and without strength training on lower extremity biomechanics. Am J Sports Med 2009; 37:1301-8. [PMID: 19299530 DOI: 10.1177/0363546509332253] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Feedback instruction is a proven modality for the alteration of motion patterns. There are no existing data on the contribution of strength training, when combined with feedback instruction, to the altering of lower extremity biomechanics. HYPOTHESIS Lower extremity muscle strength training provides an increased capacity to alter knee and hip biomechanics during a stop-jump task in response to a feedback protocol. STUDY DESIGN Controlled laboratory study. METHODS Knee and hip 3-dimensional kinematic and kinetic data were collected for 58 female recreational athletes while performing 3 stop-jump tasks after completing a 9-week strength training program (ST-FB; n = 29) or a 9-week period of no strength training (FB; n = 29). Data were then collected for both groups after completing a jump-landing feedback instruction protocol. Knee and hip joint angles, as well as resultant forces and moments, were calculated. RESULTS Across all participants, there were decreased peak vertical ground-reaction forces (P < .001) and increased knee flexion (P = .050), hip flexion (P < .001), and hip abduction (P = .032) angles, subsequent to the feedback protocol. Hip abduction angle (P < .001) increased in the ST-FB group but not the FB group, and peak knee anterior shear force (P = .015) decreased in the ST-FB group but increased in the FB group (P = .009). CONCLUSION The results indicate that strength training, when used in conjunction with video-assisted feedback, may provide an increased capacity for the alteration of knee and hip biomechanics. CLINICAL RELEVANCE Programs that include both strength training and movement education through feedback may be necessary to increase the effectiveness of anterior cruciate ligament prevention programs. Strength training may provide an increased capacity for athletes to respond to other intervention modalities used in anterior cruciate ligament injury prevention programs.
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Zinder SM, Padua DA. Reliability And Validity Of A Hand-held Myotonometer For Assessing Skeletal Muscle Stiffness. Med Sci Sports Exerc 2009. [DOI: 10.1249/01.mss.0000354721.81229.d3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Boling MC, Padua DA, Marshall S, Guskiewicz K, Pyne S, Beutler A. Gender-specific Incidence And Prevalence Of Anterior Knee Pain In A Military Population. Med Sci Sports Exerc 2009. [DOI: 10.1249/01.mss.0000356086.45985.63] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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145
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Norcross MF, Goerger BM, Blackburn JT, Padua DA. Reliability Of Single Leg Stance And MVC Methods Of Electromyography Normalization In The Lower Extremity. Med Sci Sports Exerc 2009. [DOI: 10.1249/01.mss.0000355625.10578.3d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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146
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McGrath ML, Padua DA, Lewek MD. Evidence Of Central And Peripheral Fatigue After A Functional Fatigue Protocol. Med Sci Sports Exerc 2009. [DOI: 10.1249/01.mss.0000355440.01629.9b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Goerger BM, Norcross MF, Blackburn JT, Padua DA. Lower Extremity Kinematics Of A Double Leg Jump Landing Task And Overhead Squat Are Correlated. Med Sci Sports Exerc 2009. [DOI: 10.1249/01.mss.0000354724.83015.61] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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DiStefano LJ, Padua DA, DiStefano MJ, Marshall SW. The Landing Error Scoring System Predicts Non-contact Injury In Youth Soccer Players. Med Sci Sports Exerc 2009. [DOI: 10.1249/01.mss.0000356137.20436.e0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Bell DR, Blackburn JT, Norcross MF, Ondrak KS, Hackney AC, Padua DA. The Effect Of Reproductive Hormones On Muscle Properties Across The Menstrual Cycle. Med Sci Sports Exerc 2009. [DOI: 10.1249/01.mss.0000354733.36381.fe] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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DiStefano LJ, Padua DA, DiStefano MJ, Marshall SW. Influence of age, sex, technique, and exercise program on movement patterns after an anterior cruciate ligament injury prevention program in youth soccer players. Am J Sports Med 2009; 37:495-505. [PMID: 19251685 DOI: 10.1177/0363546508327542] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Anterior cruciate ligament (ACL) injury prevention programs show promising results with changing movement; however, little information exists regarding whether a program designed for an individual's movements may be effective or how baseline movements may affect outcomes. HYPOTHESIS A program designed to change specific movements would be more effective than a "one-size-fits-all" program. Greatest improvement would be observed among individuals with the most baseline error. Subjects of different ages and sexes respond similarly. STUDY DESIGN Randomized controlled trial; Level of evidence, 1. METHODS One hundred seventy-three youth soccer players from 27 teams were randomly assigned to a generalized or stratified program. Subjects were videotaped during jump-landing trials before and after the program and were assessed using the Landing Error Scoring System (LESS), which is a valid clinical movement analysis tool. A high LESS score indicates more errors. Generalized players performed the same exercises, while the stratified players performed exercises to correct their initial movement errors. Change scores were compared between groups of varying baseline errors, ages, sexes, and programs. RESULTS Subjects with the highest baseline LESS score improved the most (95% CI, -3.4 to -2.0). High school subjects (95% CI, -1.7 to -0.98) improved their technique more than pre-high school subjects (95% CI, -1.0 to -0.4). There was no difference between the programs or sexes. CONCLUSIONS Players with the greatest amount of movement errors experienced the most improvement. A program's effectiveness may be enhanced if this population is targeted.
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