Kellie C. Huxel Bliven
Genki Hatano, Shigeyuki Suzuki, Shingo Matsuo, Satoshi Kataura, Kazuaki Yokoi, Taizan Fukaya, Mitsuhiro Fujiwara, Yuji Asai and Masahiro Iwata
Context: Hamstring injuries are common, and lack of hamstring flexibility may predispose to injury. Static stretching not only increases range of motion (ROM) but also results in reduced muscle strength after stretching. The effects of stretching on the hamstring muscles and the duration of these effects remain unclear. Objective: To determine the effects of static stretching on the hamstrings and the duration of these effects. Design: Randomized crossover study. Setting: University laboratory. Participants: A total of 24 healthy volunteers. Interventions: The torque–angle relationship (ROM, passive torque [PT] at the onset of pain, and passive stiffness) and isometric muscle force using an isokinetic dynamometer were measured. After a 60-minute rest, the ROM of the dynamometer was set at the maximum tolerable intensity; this position was maintained for 300 seconds, while static PT was measured continuously. The torque–angle relationship and isometric muscle force after rest periods of 10, 20, and 30 minutes were remeasured. Main Outcome Measures: Change in static PT during stretching and changes in ROM, PT at the onset of pain, passive stiffness, and isometric muscle force before stretching were compared with 10, 20, and 30 minutes after stretching. Results: Static PT decreased significantly during stretching. Passive stiffness decreased significantly 10 and 20 minutes after stretching, but there was no significant prestretching versus poststretching difference after 30 minutes. PT at the onset of pain and ROM increased significantly after stretching at all rest intervals, while isometric muscle force decreased significantly after all rest intervals. Conclusions: The effect of static stretching on passive stiffness of the hamstrings was not maintained as long as the changes in ROM, stretch tolerance, and isometric muscle force. Therefore, frequent stretching is necessary to improve the viscoelasticity of the muscle–tendon unit. Muscle force decreased for 30 minutes after stretching; this should be considered prior to activities requiring maximal muscle strength.
David M. Werner and Joaquin A. Barrios
Context: Core stability is considered critical for the successful execution of rehabilitative and athletic tasks. Although no consensus definition exists, different components related to core stability have been identified. An important component is the domain of motor control. There are few clinical tests assessing the motor control component of core stability (MCCS). Objective: To evaluate the interrater reliability and known-groups validity of a novel test of MCCS, the in-line half-kneeling test. The test is aimed at assessing MCCS by challenging the ability to maintain a static position with minimized contributions from the distal extremities over a minimized base of support. Design: Cross-sectional group comparison study. Setting: Laboratory. Patients or Other Participants: A total of 75 participants (25 individuals with a history of anterior cruciate ligament reconstruction, 25 uninjured Division 1 collegiate athletes, and 25 uninjured controls) were recruited from a university community. Intervention: Participants were video recorded while performing the in-line half-kneeling test for 120 seconds bilaterally. Three observers independently viewed each video to determine if individuals broke form during each test using 2 dichotomous criteria. Main Outcome Measures: Cohen’s kappa was used to assess interrater reliability, and chi-square tests of independence were used to compare break rates between groups. Results: Good-to-excellent interrater reliability (.732–.973) was seen between the 3 observers. Chi-square tests of independence revealed different break rates between all 3 groups. Compared to break rate for the reference control group (11/25—44%), those with a history of anterior cruciate ligament reconstruction broke at a higher rate (18/25—72%), whereas the uninjured collegiate athletes broke at a lower rate (4/25—16%). Conclusions: The in-line half-kneeling test is a reliable test between raters that can differentiate between groups expected to differ in MCCS.
Rosa M. Rodriguez, Ashley Marroquin and Nicole Cosby
Clinical Scenario: The anterior cruciate ligament is one of the major stabilizing ligaments of the knee joint by preventing anterior translation of the femur in the closed kinetic chain. A ruptured anterior cruciate ligament may require reconstructive surgery for patients who wish to return to physical activity. For the most part, surgeries are successful at repairing the ruptured ligament and restoring ligamentous function; the percentage of athletes that return to a competitive level of physical activity is only 44%, and 24% of patients report a main factor of preventing their return is fear of reinjury and pain. Most physiotherapy and rehabilitation research has focused on the physical treatment and is limited on the psychological aspects of recovery. Imagery has been suggested to be effective at reducing anxiety, tension, and pain, while promoting and encouraging healing after an injury. Imagery is defined as a process of performing a skill in one’s mind using the senses (touch, feel, smell, vision, etc) without any overt actions. Clinical Question: In athletes who are first-time anterior cruciate ligament reconstruction patients, does imagery training in combination with standard physical therapy reduce the fear of reinjury and pain perception? Summary of Key Findings: Previous research has primarily looked at the physical treatment aspect, and few studies have focused on the psychological factors affecting recovery. Researchers concluded that fear of reinjury was the unique predictor of return to sport even in a sample of participants that reported very little or almost no pain at all. Imagery as a therapy is an effective intervention in reducing fear of reinjury and confidence building. Furthermore, mental imagery is suggested to assist with a reduction in anxiety, pain, and tension, while promoting healing. Clinical Bottom Line: Based on the strength of recommendation taxonomy, there is a combination of level A and B evidence proposing that imagery, in combination with traditional physical therapy, can be effective at reducing psychological distress such as fear of reinjury and pain perception in first-time anterior cruciate ligament reconstruction patients.
Brad W. Willis, Katie Hocker, Swithin Razu, Aaron D. Gray, Marjorie Skubic, Seth L. Sherman, Samantha Kurkowski and Trent M. Guess
Context: Knee abduction angle (KAA), as measured by 3-dimensional marker-based motion capture systems during jump-landing tasks, has been correlated with an elevated risk of anterior cruciate ligament injury in females. Due to the high cost and inefficiency of KAA measurement with marker-based motion capture, surrogate 2-dimensional frontal plane measures have gained attention for injury risk screening. The knee-to-ankle separation ratio (KASR) and medial knee position (MKP) have been suggested as potential frontal plane surrogate measures to the KAA, but investigations into their relationship to the KAA during a bilateral drop vertical jump task are limited. Objective: To investigate the relationship between KASR and MKP to the KAA during initial contact of the bilateral drop vertical jump. Design: Descriptive. Setting: Biomechanics laboratory. Participants: A total of 18 healthy female participants (mean age: 24.1 [3.88] y, mass: 65.18 [10.34] kg, and height: 1.63 [0.06] m). Intervention: Participants completed 5 successful drop vertical jump trials measured by a Vicon marker-based motion capture system and 2 AMTI force plates. Main Outcome Measure: For each jump, KAA of the tibia relative to the femur was measured at initial contact along with the KASR and MKP calculated from planar joint center data. The coefficient of determination (r2) was used to examine the relationship between the KASR and MKP to KAA. Results: A strong linear relationship was observed between MKP and KAA (r2 = .71), as well as between KASR and KAA (r 2 = .72). Conclusions: Two-dimensional frontal plane measures show strong relationships to the KAA during the bilateral drop vertical jump.
Erik A. Wikstrom, Sajad Bagherian, Nicole B. Cordero and Kyeongtak Song
Clinical Scenario: Chronic ankle instability (CAI) is a complex musculoskeletal condition that results in sensorimotor and mechanical alterations. Manual therapies, such as ankle joint mobilizations, are known to improve clinician-oriented outcomes like dorsiflexion range of motion, but their impact on patient-reported outcomes remains less clear. Focused Clinical Question: Do anterior-to-posterior ankle joint mobilizations improve patient-reported outcomes in patients with chronic ankle instability? Summary of Key Findings: Three studies (2 randomized controlled trials and 1 prospective cohort) quantified the effect of at least 2 weeks of anterior-to-posterior ankle joint mobilizations on improving patient-reported outcomes immediately after the intervention and at a follow-up assessment. All 3 studies demonstrated significant improvements in at least 1 patient-reported outcome immediately after the intervention and at the follow-up assessment. Clinical Bottom Line: At least 2 weeks of ankle joint mobilization improves patient-reported outcomes in patients with chronic ankle instability, and these benefits are retained for at least a week following the termination of the intervention. Strength of Recommendation: Strength of recommendation is grade A due to consistent good-quality patient-oriented evidence.
Carl G. Mattacola
Kellie C. Huxel Bliven and Kelsey J. Picha
Jessica R. Fairbairn and Kellie C. Huxel Bliven
Clinical Scenario: Until recently, injury epidemiology data on elite Paralympic athletes were limited. Current data suggest high rates of shoulder injury in wheelchair athletes. Differences in shoulder injury rates between sports have not been reported in this population. Clinical Question: Is the incidence of shoulder injury in elite wheelchair athletes different between sports? Summary of Key Findings: Shoulder injury rates are high in elite wheelchair athletes, particularly in sports such as field events and fencing that require a stable base (eg, trunk, core control) from which to perform. Wheelchair racing requires repetitive motions that contribute to shoulder injuries, but rates are lower than field sports and fencing. Wheelchair curling and sledge hockey have low shoulder injury risk. Clinical Bottom Line: Shoulder injury rates vary based on sport in elite wheelchair athletes. In addition to incorporating shoulder complex specific rehabilitation for overuse shoulder injuries, clinicians should focus on core and trunk stabilization in elite wheelchair athletes competing in sports, such as field events and fencing. Strength of Recommendation: Grade C evidence exists that reports shoulder injury rates among elite wheelchair athletes differ based on sport participation.