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).

Putting "Heavy" into Heavy Slow Resistance.

The body of literature on tendinopathy management has come a long way in the last few decades and a variety of changes in the clinical approach have emerged from this research. One particular approach that shows promise has been called "heavy slow resistance" (HSR), and this has been the subject of investigation in a number of randomized controlled trials. While the premise for this approach is defensible, a critical examination of the implementation of these HSR protocols results in some concerns when compared to basic exercise science principles. This article lays out some considerations that will help future investigators to improve their exercise prescription approaches in this area.

A Multi-Systems Approach to Human Movement after ACL Reconstruction: The Cardiopulmonary System.

The cardiopulmonary system plays a pivotal role in athletic and rehabilitative activities following anterior cruciate ligament reconstruction, along with serving as an important support for the functioning of other physiologic systems including the integumentary, musculoskeletal, and nervous systems. Many competitive sports impose high demands upon the cardiorespiratory system, which requires careful attention and planning from rehabilitation specialists to ensure athletes are adequately prepared to return to sport. Cardiopulmonary function following anterior cruciate ligament reconstruction (ACLR) can be assessed using a variety of methods, depending on stage of healing, training of the clinician, and equipment availability. Reductions in cardiovascular function may influence the selection and dosage of interventions that are not only aimed to address cardiopulmonary impairments, but also deficits experienced in other systems that ultimately work together to achieve goal-directed movement. The purpose of this clinical commentary is to present cardiopulmonary system considerations within a multi-physiologic systems approach to human movement after ACLR, including a clinically relevant review of the cardiopulmonary system, assessment strategies, and modes of cardiopulmonary training to promote effective, efficient movement. LEVEL OF EVIDENCE: 5.

A Multi-Systems Approach to Human Movement after ACL Reconstruction: The Musculoskeletal System.

Several negative adaptations to the musculoskeletal system occur following anterior cruciate ligament (ACL) injury and ACL reconstruction (ACLR) such as arthrogenic muscle inhibition, decreased lower extremity muscle size, strength, power, as well as alterations to bone and cartilage. These changes have been associated with worse functional outcomes, altered biomechanics, and increased risk for re-injury and post-traumatic osteoarthritis. After ACL injury and subsequent ACLR, examination and evaluation of the musculoskeletal system is paramount to guiding clinical decision making during the rehabilitation and the return to sport process. The lack of access many clinicians have to devices necessary for gold standard assessment of muscle capacities and force profiles is often perceived as a significant barrier to best practices. Fortunately, testing for deficits can be accomplished with methods available to the clinician without access to costly equipment or time-intensive procedures. Interventions to address musculoskeletal system deficits can be implemented with a periodized program. This allows for restoration of physical capacities by adequately developing and emphasizing physical qualities beginning with mobility and movement, and progressing to work capacity and neuromuscular re-education, strength, explosive strength, and elastic or reactive strength. Additional considerations to aid in addressing strength deficits will be discussed such as neuromuscular electrical stimulation, volume and intensity, eccentric training, training to failure, cross-education, and biomechanical considerations. The American Physical Therapy Association adopted a new vision statement in 2013 which supported further development of the profession's identity by promoting the movement system, yet validation of the movement system has remained a challenge. Application of a multi-physiologic systems approach may offer a unique understanding of the musculoskeletal system and its integration with other body systems after ACLR. The purpose of this clinical commentary is to highlight important musculoskeletal system considerations within a multi-physiologic system approach to human movement following ACLR. LEVEL OF EVIDENCE: 5.

Blood Flow Restriction Training.

Muscle weakness and atrophy are common impairments after musculoskeletal injury. Blood flow restriction (BFR) training offers the ability to mitigate weakness and atrophy without overloading healing tissues. It appears to be a safe and effective approach to therapeutic exercise in sports medicine environments. This approach requires consideration of a wide range of factors, and the purpose of our article is to provide insights into proposed mechanisms of effectiveness, safety considerations, application guidelines, and clinical recommendations for BFR training after musculoskeletal injury. Whereas training with higher loads produces the most substantial increases in strength and hypertrophy, BFR training appears to be a reasonable option for bridging earlier phases of rehabilitation when higher loads may not be tolerated by the patient and later stages that are consistent with return to sport.

ENERGY SYSTEM DEVELOPMENT AND LOAD MANAGEMENT THROUGH THE REHABILITATION AND RETURN TO PLAY PROCESS.

Return-to-play from injury is a complex process involving many factors including the balancing of tissue healing rates with the development of biomotor abilities. This process requires interprofessional cooperation to ensure success. An often-overlooked aspect of return-to-play is the development and maintenance of sports specific conditioning while monitoring training load to ensure that the athlete's training stimulus over the rehabilitation period is appropriate to facilitate a successful return to play. The purpose of this clinical commentary is to address the role of energy systems training as part of the return-to-play process. Additionally the aim is to provide practitioners with an overview of practical sports conditioning training methods and monitoring strategies to allow them to direct and quantify the return-to-play process. LEVEL OF EVIDENCE: 5.

CURRENT CONCEPTS IN PERIODIZATION OF STRENGTH AND CONDITIONING FOR THE SPORTS PHYSICAL THERAPIST.

UNLABELLED: The rehabilitation process is driven by the manipulation of training variables that elicit specific adaptations in order to meet established goals. Periodization is an overall concept of training that deals with the division of the training process into specific phases. Programming is the manipulation of the variables within these phases (sets, repetitions, load) that are needed to bring about the specific adaptations desired within that particular period. The current body of literature is very limited when it comes to how these variables are best combined in an injured population since most of the periodization research has been done in a healthy population. This manuscript explores what is currently understood about periodization, gives clinical guidelines for implementation, and provides the sports physical therapist with a framework to apply these principles in designing rehabilitation programs. LEVEL OF EVIDENCE: 5.