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.
Marissa J. Basar, Justin M. Stanek, Daniel D. Dodd and Rebecca L. Begalle
Context: The functional movement screen (FMS) is a tool designed to identify limitations between sections of the body during fundamental movements. However, there is limited evidence on the effectiveness of corrective exercises to improve FMS scores. Objective: To examine the effects of individualized corrective exercises on improving FMS scores in Reserve Officers’ Training Corps cadets and to correlate these changes with physical fitness performance as established with the standard Army Physical Fitness Test (APFT). Design: Cluster randomized, cohort study. Setting: Controlled laboratory setting (FMS) and a field-based setting (APFT). Participants: Forty-four healthy, physically active cadets met all inclusion and exclusion criteria. Intervention: Participants were randomly assigned to the experimental (n = 24) or control (n = 20) group by cluster. Personalized intervention programs were developed through the FMS Pro360 system, a subscription-based software that generates corrective exercises based on individual FMS test scores. The experimental group performed the individualized programs 3 times per week for 4 weeks prior to morning physical training regime. The control group continued to participate in the standard warm-up drills as part of morning physical training. Main Outcome Measures: The dependent variables included the individual and composite FMS and APFT scores. Scores were reported and analyzed in several ways to determine the efficacy of corrective exercises. Results: Group FMS and APFT scores were similar at pretest. The experimental group had a significantly greater improvement in FMS composite score at 4 weeks post (U = 87; z = −3.83; P = .001; effect size = 1.33; 95% confidence interval, 0.69–1.98). No significant changes in APFT scores were found (U = 237.5, z = −0.33, P = .74). A nonsignificant weak correlation between the FMS and APFT scores (r = .25, P = .10) was found. Conclusion: Individualized corrective exercises improved FMS scores, but did not change physical fitness performance. FMS composite scores and APFT performance are not related.
Jonathan S. Goodwin, Robert A. Creighton, Brian G. Pietrosimone, Jeffery T. Spang and J. Troy Blackburn
Context: Orthotic devices such as medial unloader knee braces and lateral heel wedges may limit cartilage loading following trauma or surgical repair. However, little is known regarding their effects on gait biomechanics in young, healthy individuals who are at risk of cartilage injury during physical activity due to greater athletic exposure compared with older adults. Objective: Determine the effect of medial unloader braces and lateral heel wedges on lower-extremity kinematics and kinetics in healthy, young adults. Design: Cross-sectional crossover design. Setting: Laboratory setting. Patients: Healthy, young adults who were recreationally active (30 min/d for 3 d/wk) between 18 and 35 years of age, who were free from orthopedic injury for at least 6 months, and with no history of lower-extremity orthopedic surgery. Interventions: All subjects completed normal over ground walking with a medial unloader brace at 2 different tension settings and a lateral heel wedge for a total of 4 separate walking conditions. Main Outcome Measures: Frontal plane knee angle at heel strike, peak varus angle, peak internal knee valgus moment, and frontal plane angular impulse were compared across conditions. Results: The medial unloader brace at 50% (−2.04° [3.53°]) and 100% (−1.80° [3.63°]) maximum load placed the knee in a significantly more valgus orientation at heel strike compared with the lateral heel wedge condition (−0.05° [2.85°]). However, this difference has minimal clinical relevance. Neither of the orthotic devices altered knee kinematics or kinetics relative to the control condition. Conclusions: Although effective in older adults and individuals with varus knee alignment, medial unloader braces and lateral heel wedges do not influence gait biomechanics in young, healthy individuals.
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 (r2 = .72). Conclusions: Two-dimensional frontal plane measures show strong relationships to the KAA during the bilateral drop vertical jump.
Carl G. Mattacola, Carolina Quintana, Jed Crots, Kimberly I. Tumlin and Stephanie Bonin
Context: During thoroughbred races, jockeys are placed in potentially injurious situations, often with inadequate safety equipment. Jockeys frequently sustain head injuries; therefore, it is important that they wear appropriately certified helmets. Objective: The goals of this study are (1) to perform impact attenuation testing according to ASTM F1163-15 on a sample of equestrian helmets commonly used by jockeys in the United States and (2) to quantify headform acceleration and residual crush after repeat impacts at the same location. ParticipantsandDesign: Seven helmet models underwent impact attenuation testing according to ASTM F1163-15. A second sample of each helmet model underwent repeat impacts at the crown location for a total of 4 impacts. Setting : Laboratory. Intervention : Each helmet was impacted against a flat and equestrian hazard anvil. MainOutcome Measures: Headform acceleration was recorded during all impact and computed tomography scans were performed preimpact and after impacts 1 and 4 on the crown to quantify liner thickness. Results: Four helmets had 1 impact that exceeded the limit of 300g. During the repeated crown impacts, acceleration remained below 300g for the first and second impacts for all helmets, while only one helmet remained below 300g for all impacts. Foam liner thickness was reduced between 5% and 39% after the first crown impact and between 33% and 70% after the fourth crown impact. Conclusions: All riders should wear a certified helmet and replace it after sustaining a head impact. Following an impact, expanded polystyrene liners compress, and their ability to attenuate head acceleration during subsequent impacts to the same location is reduced. Replacing an impacted helmet may reduce a rider’s head injury risk.
Selvin Balki and Hanım Eda Göktas¸
Objective: Kinesio taping® (KT) is a widely used treatment method in musculoskeletal rehabilitation. Little is known about the KT treatment and hip strength in patients with anterior cruciate ligament reconstruction (ACLR). The purpose of this study was to investigate the effectiveness of the KT treatment on hip muscle weakness in early rehabilitation of ACLR and the possible determinants of the ACLR-hip strength deficit (HSD). Design: Double-blind sham-controlled study. Setting: Rehabilitation department. Patients: A total of 26 male patients who underwent unilateral ACLR using hamstring autograft or allograft 4 days before. Interventions: The patients were randomized to receive the knee KT treatment (n = 13) with lymphatic correction plus muscle (biceps/rectus femoris) facilitation or sham KT (n = 13) for 10 days. In addition, the same ACLR rehabilitation program was applied to all the patients. Main Outcome Measures: The baseline data included demographic and clinical characteristics, postoperative swelling, knee motion loss and knee pain, and bilateral strength of the knee and hip muscle groups, except for rotator. Then, percentage values of hip HSD and knee strength limb symmetry index were calculated. The hip strength measurements in ACLR-operated leg were repeated on the 5th to 10th days of KT. Results: Changes in all hip strength values over time were significant in both groups (P < .01). In intergroup analysis of 5th and 10th days, improvements in the flexor (only 10th day), extensor, and adductor hip strength on operated leg were in favor of KT group (P < .05). In addition, the postoperative thigh swelling and knee strength limb symmetry index values were correlated with the HSD outcomes in baseline data (P < .05). Conclusions: ACLR-HSD can be caused by postoperative increased swelling and reduced knee strength. The KT treatment with lymphatic correction and muscle facilitation can be used in the treatment of postoperative hip muscle weakness after ACLR.