Inline dynamometry provides reliable measurements of quadriceps strength in healthy and ACL-reconstructed individuals and is a valid substitute for isometric electromechanical dynamometry following ACL reconstruction.

BACKGROUND: Quadriceps strength testing is recommended to guide rehabilitation and mitigate the risk of second injury following anterior cruciate ligament (ACL) reconstruction. Hand-held dynamometry is a practical alternative to electromechanical dynamometry but demonstrates insufficient reliability and criterion validity in healthy and ACL-reconstructed participants respectively. The purpose of this study is to investigate the reliability and concurrent validity of inline dynamometry for measuring quadriceps strength. The hypotheses are that intra-class correlation coefficient (ICC) values will be >0.90 for reliability and concurrent validity. METHODS: This was a cross sectional study using a within-participant, repeated measures design. Isometric quadriceps testing was performed at 60° knee flexion in 50 healthy and 52 ACL-reconstructed participants. Interrater reliability, intrarater reliability, and concurrent validity of inline dynamometry was investigated through calculation of ICCs, Bland-Altman analysis, linear regression, standard error of measurement (SEM) and minimal detectable change (MDC). RESULTS: The lower bounds of the 95% confidence intervals were >0.90 for all reliability and validity ICCs in healthy and ACL-reconstructed participants, except for intrarater reliability in healthy participants using absolute scores (ICC = 0.936 [95% CI 0.890-0.963]). In ACL-reconstructed participants, Bland-Altman bias was 0.01 Nm/kg for absolute and average scores, limits of agreement were -11.74% to 12.59% for absolute scores, the SEM was 0.13Nm/kg (95% CI 0.10-0.17) and the MDC was 0.36Nm/kg (95% CI 0.28 - 0.47). CONCLUSION: Inline dynamometry is a reliable and economical alternative to electromechanical dynamometry for the assessment of quadriceps strength following ACL-reconstruction. CLINICAL TRIAL REGISTRATION NUMBER: ClinicalTrials.gov (NCT05109871).

CURRENT CONCEPTS IN BIOMECHANICAL INTERVENTIONS FOR PATELLOFEMORAL PAIN.

Patellofemoral pain (PFP) has historically been a complex and enigmatic issue. Many of the factors thought to relate to PFP remain after patients' symptoms have resolved making their clinical importance difficult to determine. The tissue homeostasis model proposed by Dye in 2005 can assist with understanding and implementing biomechanical interventions for PFP. Under this model, the goal of interventions for PFP should be to re-establish patellofemoral joint (PFJ) homeostasis through a temporary alteration of load to the offended tissue, followed by incrementally restoring the envelope of function to the baseline level or higher. High levels of PFJ loads, particularly in the presence of an altered PFJ environment, are thought to be a factor in the development of PFP. Clinical interventions often aim to alter the biomechanical patterns that are thought to result in elevated PFJ loads while concurrently increasing the load tolerance capabilities of the tissue through therapeutic exercise. Biomechanics may play a role in PFJ load modification not only when addressing proximal and distal components, but also when considering the involvement of more local factors such as the quadriceps musculature. Biomechanical considerations should consider the entire kinetic chain including the hip and the foot/ankle complex, however the beneficial effects of these interventions may not be the result of long-term biomechanical changes. Biomechanical alterations may be achieved through movement retraining, but the interventions likely need to be task-specific to alter movement patterns. The purpose of this commentary is to describe biomechanical interventions for the athlete with PFP to encourage a safe and complete return to sport. LEVEL OF EVIDENCE: 5.

Sports participation following total hip arthroplasty.

UNLABELLED: Total Hip Athroplasty (THA) is a common procedure in orthopedic surgery to address severe osteoarthritis (OA) in the hip joint. With the burgeoning "baby boomer" generation and older athletes who wish to return to competitive levels of sports, understanding how sporting activity affects THA outcomes is becoming exceptionally important. The purpose of this review is to characterize the current recommendations and risks for returning to sports after THA, as well as discuss the implications of the changing demographic and level of expectation on rehabilitation paradigms. Although the actual risks associated with participating in sports after THA are unknown, there are concerns that higher levels of physical activity after THA may increase risk for fracture, dislocation and poor long-term outcomes. Evidence surrounding the specific effect of sporting activity on wear after THA is conflicting. Newer alternatives such as metal-on-metal hip resurfacing are expected to provide better durability but there are concerns of systemic metal ions from mechanical wear, although the impact of these ions on patient health is not clear. Tracking outcomes in patients participating in higher level activities after THA presents a problem. Recently the High Activity Arthroplasty Score has been developed in response to the need to quantify higher level of physical activity and sports participation after joint arthroplasty. This measure has been shown to have a higher ceiling effect than other common outcome measures. There is little prospective evidence regarding the likelihood of poor clinical outcomes with higher level of sporting activity. There is some evidence to suggest that wear may be related to activity level, but the impact on clinical outcomes is conflicting. When advising an athlete considering returning to sport after THA, consider their preoperative activity level, current physical fitness, and specific history including bone quality, surgical approach and type of prosthesis. LEVEL OF EVIDENCE: 5.

Core stabilization exercise prescription, part I: current concepts in assessment and intervention.

CONTEXT: Injury to the low back can cause significant pain and dysfunction, which can affect an athlete's performance and result in time lost from sport. A common conservative treatment is therapeutic core stabilization exercises, which can address pain and musculoskeletal dysfunction in patients with low back pathology. EVIDENCE ACQUISITION: MEDLINE and CINAHL were searched (from 1966 to March 2013) to identify relevant research. Keywords and keyword combinations searched included motor control exercise, segmental stabilization, core stabilization, transversus abdominis, multifidi, and low back pain. RESULTS: There are 2 popular rehabilitation strategies to assess core function and promote core stabilization. Each has been developed based on biomechanical models of lumbar segmental stability and observed motor control dysfunction in patients with low back pain. CONCLUSION: Controversy exists among clinical and research groups as to the optimal strategy for an athlete with low back pain.

Core stabilization exercise prescription, part 2: a systematic review of motor control and general (global) exercise rehabilitation approaches for patients with low back pain.

CONTEXT: Therapeutic exercises are frequently prescribed to patients with low back pain. Numerous exercise programs for patients with low back pain have been described. Many of these treatment programs are based on 1 of 2 popular rehabilitation strategies: a motor control exercise approach or a general exercise approach. DATA SOURCES: PubMed clinical queries from 1966 to March 2013 for keyword combinations including motor control exercise, core stability exercise, therapeutic exercise, general exercise, global exercise, local exercise, transversus abdominis, segmental stabilization, and low back pain. STUDY SELECTION: Randomized controlled trials that assessed the effects of a motor control exercise approach, a general exercise approach, or both for patients with low back pain that were published in scientific peer-reviewed journals. DATA EXTRACTION: Included studies underwent appraisal for exercise intervention and outcomes. RESULTS: Fifteen studies were identified (8, motor control exercise approach without general exercise comparison; 7, general exercise approach with or without motor control exercise approach comparison). Current evidence suggests that exercise interventions may be effective at reducing pain or disability in patients with low back pain. CONCLUSION: Stabilization exercises for patients with low back pain may help to decrease pain and disability. It may not be necessary to prescribe exercises purported to restore motor control of specific muscles.

Influence of the hip on patients with patellofemoral pain syndrome: a systematic review.

CONTEXT: Patellofemoral pain syndrome (PFPS) is one of the most common conditions limiting athletes. There is a growing body of evidence suggesting that dysfunction at the hip may be a contributing factor in PFPS. DATA SOURCES: MEDLINE (1950-September 2010), CINAHL (1982-September 2010), and SPORTDiscus (1830-September 2010) were searched to identify relevant research to this report. STUDY SELECTION: Studies were included assessing hip strength, lower extremity kinematics, or both in relation to PFPS were included. DATA EXTRACTION: Studies included randomized controlled trials, quasi-experimental designs, prospective epidemiology, case-control epidemiology, and cross-sectional descriptive epidemiology in a scientific peer-reviewed journal. RESULTS: PFPS is associated with decreased hip strength, specifically at the abductors and external rotators. There is a correlation between PFPS and faulty hip mechanics (adduction and internal rotation). CONCLUSIONS: There is a link between the strength and position of the hip and PFPS. These patients have a common deficit once symptomatic. Hip strengthening and a coordination program may be useful in a conservative treatment plan for PFPS.

Comprehensive strength training program for a recreational senior golfer 11-months after a rotator cuff repair.

BACKGROUND AND PURPOSE: Golf is a popular sport played by hundreds of thousands of individuals of all ages and of varying skill levels. An orthopedic or sports-related injury and/or surgery may limit an individual's sport participation, require him/her to complete a course of rehabilitation, and initiate (or resume) a sport-specific training program. Unlike the availability of evidence to guide postsurgical rehabilitation and sport-specific training of athletes from sports other than golf, there have only been two reports describing outcomes after surgery and for golfers. The purpose of this case report is to present a post-rehabilitation return to sport-training program for a recreational golfer 11-months after a rotator cuff repair. CASE DESCRIPTION: The subject, a 67-year old female, injured her right shoulder requiring a rotator cuff repair 11-months prior to her participation in a golf fitness training program. The subject participated in six training sessions over seven week period consisting of general strengthening exercises (including exercises for the rotator cuff), exercises for the core, plyometrics, and power exercises. OUTCOMES: The subject made improvements in power and muscular endurance of the core. She was able to resume golf at the completion of the training program. DISCUSSION: The subject was able to make functional improvements and return to golf after participation in a comprehensive strength program. Additional studies are necessary to improve program design for golfers who wish to return to sport after shoulder surgery.

Minimizing injuries and enhancing performance in golf through training programs.

CONTEXT: Golf is a popular sport, particularly in older populations. Regardless of age and skill level, golfers risk injury to the back, shoulder, wrist and hand, elbow, and knee. Because of the unique compressive, shear, rotational, and lateral bending forces created in the lumbar region during the golf swing, the primary sport-related malady experienced by amateurs and professionals is low back pain. Extrinsic and intrinsic injury risk factors have been reported in the literature. A growing body of evidence supports the prescription of strength training routines to enhance performance and reduce the risk of injury. EVIDENCE ACQUISITION: Relevant studies were reviewed on golf injuries, swing mechanics, training routines, and general training program design. The following electronic databases were used to identify research relevant to this report: MEDLINE (from 1950-November 2009), CINAHL (1982-November 2009), and SPORTDiscus (1830-November 2009). RESULTS: Injuries may be associated with lack of warm-up, poor trunk flexibility and strength, faulty swing technique, and overuse. CONCLUSIONS: Implementing a training program that includes flexibility, strength, and power training with correction of faulty swing mechanics will help the golfer reduce the likelihood of injury and improve overall performance.

Incorporating kettlebells into a lower extremity sports rehabilitation program.

The primary goal of a sports rehabilitation program is to return the injured athlete back to competition as quickly and as safely as possible. Sports physical therapists utilize a variety of exercise equipment to help an athlete restore function after an injury. An injured athlete's therapeutic exercise program frequently includes the prescription of functional strengthening and power exercises during the later stages of rehabilitation. One piece of exercise equipment, the kettlebell, has gained popularity for its ability to allow the user to perform functional power exercises. The unique exercises that can be performed with kettlebells may have utility in sports physical therapy practice. This clinical suggestion outlines the clinical rationale for the inclusion of kettlebell exercises when rehabilitating an athlete with a lower extremity injury.