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Clinical Scenario: Nearly 60 million youth ages 6–18 participate in athletics within the United States. Over the last 30 years, the outlook on youth sport participation has drastically changed, resulting in an increased emphasis on performance and college sport participation. These evolving expectations have created a sense of perfectionism, demanding more time and energy to be placed into a single sport, resulting in an increased prevalence of sport specialization, and consequently, an increased rate of injury. Clinical Question: What is the impact of sport specialization on lower-extremity neuromuscular control in female adolescent athletes? Summary of Key Findings: Four studies were included, all comparing movement efficiency and movement patterns among multisport and sport-specialized female adolescent athletes. Three studies showed that sport specialization is associated with lower-extremity biomechanical alterations that are indicative of altered levels of neuromuscular control, which can predispose an individual to an increased risk of injury. One study concluded that no differences in neuromuscular control exist when comparing sport-specialized to multisport adolescent female athletes. Clinical Bottom Line: Sport specialization has the potential to create negative alterations in a female adolescent athletes’ lower-extremity biomechanics, leading to the creation of altered levels of neuromuscular control and a possible increased risk for injury. Strength of Recommendation: Level B evidence exists to support the conclusion that sport specialization negatively affects a female adolescent athlete’s lower-extremity neuromuscular control.

Background: Low-intensity resistance exercise therapy (LIRET) based on myofascial chains, applied to both affected and nonlocal joints, is an effective method for knee osteoarthritis (OA) rehabilitation. This study applied LIRET in a comparison of prevalues and postvalues of lower-limb tension in female patients with knee OA and asymptomatic participants. Methods: Twenty-four female participants with knee OA and 20 asymptomatic women took part in a 3-month long application of LIRET. Participants’ ankle passive torque and ankle range of motion in the sagittal plane were assessed with an isokinetic dynamometer. The collected values were used to estimate the sagittal-plane lower-limb tension. Results: Compared with the asymptomatic group, participants with knee OA presented decreased maximum ankle dorsiflexion (P < .001), decreased ankle plantar flexion range (P = .023), ankle resting position more inclined to dorsiflexion (P = .017), increased ankle dorsiflexion stiffness (P = .005), and lower ankle plantar flexion stiffness (P = .034). After exercise intervention, the knee OA group self-reported less knee pain (P < .001), improved physical function (P < .001), increased maximum dorsiflexion (P = .021), and increased plantar flexion range (P < .001). While plantar flexion stiffness increased (P = .037), dorsiflexion stiffness decreased (P = .015) and ankle resting position moved toward dorsiflexion (P = .002). Results suggest possible decreased anterior leg tension and possible increased posterior leg tension in patients with knee OA. Conclusions: The results supported that knee OA patients present imbalanced myofascial tension of lower limbs. LIRET based on myofascial chains appears to decrease pain, and stiffness, and improve physical function of patients with knee OA and change their lower-limb tension.

Context: Hip muscle imbalance, especially between gluteal muscles and tensor fasciae latae (TFL), is one of the risk factors for developing low back pain which should be considered in rehabilitation programs. This study compared the effect of exercises with gluteal-to-TFL muscle activation index above and below 50 on pain intensity, disability, and lower limbs’ range of motion (ROM) in patients with nonspecific chronic low back pain. Design: A semiexperimental intervention study with a pretest and posttest. Methods: A total of 45 patients with nonspecific chronic low back pain were randomly divided into 2 experimental groups of gluteal-to-TFL muscle activation index above 50 (n = 15), below 50 (n = 15), and a control group (n = 15). Pain intensity (visual analog scale), disability (Roland–Morris Disability Questionnaire), and lower limbs’ ROM including hip extension, hip abduction, hip external rotation, and knee extension (goniometer) were assessed at pretest and after 8 weeks of intervention. Results: Within-group comparison showed significant improvement of pain, disability, and ROMs in both experimental groups. No significant changes were observed in the control group. In between-group analysis, significant differences were observed in group of gluteal-to-TFL muscle activation index above 50 for only pain (P = .03) and disability (P = .01). For ROMs, although clinical improvement of lower limbs’ ROMs was higher in group of gluteal-to-TFL muscle activation index above 50, no statistically significant differences were found between 2 experimental groups. Both experimental groups were superior to the control group for all outcomes. Conclusions: Findings indicate the statistically and clinically superior effectiveness of exercises with a gluteal-to-TFL muscle activation index above 50 in the reduction of pain and disability. Based on the clinical significance of exercises with a gluteal-to-TFL muscle activation index above 50 for improving ROMs, utilizing specific exercises that more activated gluteal muscle compared to TFL is recommended for patient with restricted lower limbs’ ROMs.

Clinical Scenario: Stress fractures are one of the most common injuries in athletes. Unfortunately, they are hard to diagnose, require multiple radiology exams and follow-up which leads to more exposure to radiation and an increase in cost. Stress fractures that are mismanaged can lead to serious complications and poorer outcomes for the athlete. During the rehabilitation process, it would be beneficial to be able to monitor the healing of fractures to know when it is safe to gradually allow a patient to a return to sport because the return to activity is not usually objective and based on pain level. Clinical Question: Can infrared thermography (IRT) be a useful tool to measure the pathophysiological state of the fracture healing? The aim of this critically appraised topic is to analyze the current evidence of IRT for measuring the temperature change in fractures to provide recommendations for medical practitioners. Summary of Key Findings: For this critically appraised topic, we examined 3 articles that compared medical imaging and IRT over multiple time points during the follow-up. The 3 articles concluded that a 1 °C asymmetry in temperature followed by a return to normal (less than 0.3 °C) temperature during the healing process of fractures can be monitored using IRT. Clinical Bottom Line: Once the patient has been diagnosed with a fracture, IRT can safely be used to monitor the evolution of a fracture. When the thermogram progresses from a hot thermogram to a cold thermogram, the healing is considered good enough to return to sport. Strength of Recommendation: Grade 2 evidence exists to support IRT being used by clinicians to monitor fracture healing. Due to the limited research and novelty of the technology, the current recommendations are for following the treatment of the fracture once the initial diagnosis is made.

Clinical Scenario: Tendinopathy is a musculoskeletal pathological condition experienced by athletes that can result in pain, impaired muscle performance, and loss of physical function and can hinder return to sports. Various types of resistance exercise training are effective for treating tendinopathy, including isometric, concentric, eccentric, and high-load slow-velocity resistance exercise. Clinical Question: What are the effects of high-load slow-velocity resistance exercise training, compared with other forms of resistance exercise, on tendon morphology and patient-reported outcomes in athletes with tendinopathy? Summary of Key Findings: The findings of 4 randomized clinical trials were included. One study compared high-load slow-velocity resistance exercise with moderate-load slow-velocity resistance exercise. Two studies investigated the effects of high-load slow-velocity resistance exercise versus eccentric resistance exercise. The fourth study compared high-load slow-velocity resistance exercise with inertia-based resistance exercise. In all of the studies, high-load slow-velocity resistance exercise was as effective as the other forms of resistance exercise for improving patient-reported outcomes and pain. Three studies found no significant differences in changes in tendon morphology between patients who received high-load slow-velocity resistance exercise versus those who received the other forms of resistance exercise. One study showed that high-load slow-velocity resistance exercise was more effective than eccentric exercise for improving tendon morphology outcomes. Clinical Bottom Line: Current evidence supports the use of high-load slow-velocity resistance exercise as a treatment option for patellar and Achilles tendinopathy in athletes. Strength of Recommendation: Results from level 2 studies suggest grade B evidence in support of high-load slow-velocity resistance exercise for treating athletes with tendinopathy.

Context: Different resistance exercise determinants modulate the musculotendinous adaptations following eccentric hamstring training. The Nordic Hamstring Exercise (NHE) can be performed 2-fold: the movement velocity irreversibly increases toward the end of the range of motion or it is kept constant. Design: This cross-sectional study aimed to investigate if the downward acceleration angle (DWA_angle) can be used as a classification parameter to distinguish between increasing and constant velocity NHE execution. Furthermore, the kinetic and kinematic differences of these 2 NHE execution conditions were examined by analyzing the DWA_angle in relation to the angle of peak moment. Methods: A total of 613 unassisted NHE repetitions of 12 trained male sprinters (22 y, 181 cm, 76 kg) were analyzed. Results: The majority of analyzed parameters demonstrated large effects. NHEs with constant velocity  (n = 285) revealed significantly higher impulses (P < .001; d = 2.34; + 61%) and fractional time under tension (P < .001; d = 1.29; +143%). Although the generated peak moments were significantly higher for constant velocity (P = .003; d = 0.29; +4%), they emerged at similar knee flexion angles (P = .167; d = 0.28) and revealed on average just low relationships to the DWA_angle ( $R_{\mathrm{mean}}^2=22.4\%$ ). DWA_angle highly correlated with the impulse ( $R_{\mathrm{mean}}^2=60.8\%$ ) and δ (DWA_angle–angle of peak moment; $R_{\mathrm{mean}}^2=83.6\%$ ). Conclusions: Relating DWA_angle to angle of peak moment assists to distinguish between significantly different NHE execution, which will potentially elicit different musculotendinous adaptations. These insights are essential for coaches and athletes to understand how to manipulate eccentric hamstring training to change its purpose.

Context: Current lower-extremity return to sport testing primarily considers the physical status of an athlete; however, sport participation requires continuous cognitive dual-task engagement. Therefore, the purpose was to develop and evaluate the reliability of a visual-cognitive reactive (VCR) triple hop test that simulates the typical sport demand of combined online visual-cognitive processing and neuromuscular control to improve return to sport testing after lower-extremity injury. Design: Test–retest reliability. Methods: Twenty-one healthy college students (11 females, 23.5 [3.7] y, 1.73 [0.12] m, 73.0 [16.8] kg, Tegner Activity Scale 5.5 [1.1] points) participated. Participants performed a single-leg triple hop with and without a VCR dual task. The VCR task incorporated the FitLight system to challenge peripheral response inhibition and central working memory. Maximum hop distance, reaction time, cognitive errors, and physical errors were measured. Two identical testing visits were separated by 12 to 17 days (14 [1] d). Results: Traditional triple hop (intraclass correlation coefficients: ICC_(3,1) = .96 [.91–.99]; standard error of the measurement = 16.99 cm) and the VCR triple hop (intraclass correlation coefficients_(3,1) = .92 [.82–.97]; standard error of the measurement = 24.10 cm) both demonstrated excellent reliability for the maximum hop distance, and moderate reliability for the VCR triple hop reaction time (intraclass correlation coefficients_(3,1) = .62 [.09–.84]; standard error of the measurement = 0.09 s). On average, the VCR triple hop resulted in a hop distance deficit of 8.17% (36.4 [5.1] cm; P < .05, d = 0.55) relative to the traditional triple hop. Conclusions: Hop distance on the VCR triple hop had excellent test–retest reliability and induced a significant physical performance deficit when compared with the traditional triple hop assessment. The VCR triple hop reaction time also demonstrated moderate reliability.

Context: The assessment of strength is one of the most usual practices among professionals involved in health care or sport. Quadriceps and hamstrings are the most commonly assessed muscle groups. Generally, the methods used to assess muscle strength are active and, therefore, alternative passive methods could be useful. Myoton provides measures on 3 mechanical properties of the muscle: tone, elasticity, and stiffness. Objective: This study aimed to analyze the association of Myoton, an easy-to-use tool not requiring voluntary stimulus from the subject, with strength values in quadriceps and hamstrings. Study Design: Experimental. Setting: University kinesiology laboratory. Participants: Thirty-eight recreational athletes were evaluated. Main Outcome Measures: Anthropometric and demographic data, Myoton-based measures of vastus lateralis, rectus femoris, vastus medialis, biceps femoris, and semitendinosus, and the maximum voluntary isometric contraction of quadriceps and hamstrings. Procedures: The association was examined using multiple regression models to estimate strength through Myoton-based parameters and different patient characteristics. The models encompassed either 2 or 3 independent variables. Results: The adjusted R ² values for predicting quadriceps strength were .666 for rectus femoris, .726 for vastus lateralis, and .667 for vastus medialis, while in regard to hamstrings, they were .617 for biceps femoris and .604 for semitendinosus. Conclusions: The main finding was that acceptable relationships were found between muscle strength and Myoton-based parameters when variables such as gender and/or age are considered. Our study reveals a new tool for estimating strength with outstanding advantages: it is easy, time-efficient, adaptable, and highly manageable through the feasible equations provided.