SYNOPSIS: The sport of volleyball creates considerable dynamic trunk stability demands. Back injury occurs all too frequently in volleyball, particularly among female athletes. The purpose of this clinical commentary is to review functional anatomy, muscle coactivation strategies, assessment of trunk muscle performance, and the characteristics of effective exercises for the trunk or core. From this information, a conceptual progressive 3-phase volleyball-specific training program is presented to improve dynamic trunk stability and to potentially reduce the incidence of back injury among volleyball athletes. Phase 1 addresses low-velocity motor control, kinesthetic awareness, and endurance, with the clinician providing cues to teach achievement of biomechanically neutral spine alignment. Phase 2 focuses on progressively higher velocity dynamic multiplanar endurance, coordination, and strength-power challenges integrating upper and lower extremity movements, while maintaining neutral spine alignment. Phase 3 integrates volleyball-specific skill simulations by breaking down composite movement patterns into their component parts, with differing dynamic trunk stability requirements, while maintaining neutral spine alignment. Prospective research is needed to validate the efficacy of this program. LEVEL OF EVIDENCE: Level 5.

J Orthop Sports Phys Ther. 2008; 38(11):703-720, Epub 24 October 2008. doi:10.2519/jospt.2008.2814

KEY WORDS: abdominal muscles, electromyography, erector spinae, kinetics, lumbar spine

We present a clinical commentary of existing evidence regarding popliteus musculotendinous complex anatomy, biomechanics, muscle activation, and kinesthesia as they relate to functional knee joint rehabilitation. The popliteus appears to act as a dynamic guidance system for monitoring and controlling subtle transverse- and frontal-plane knee joint movements, controlling anterior-posterior lateral meniscus movement, unlocking and internally rotating the knee joint (tibia) during flexion initiation, assisting with 3-dimensional dynamic lower extremity postural stability during single-leg stance, preventing forward femoral dislocation on the tibia during flexed-knee stance, and providing for postural equilibrium adjustments during standing. These functions may be most important during mid-range knee flexion when capsuloligamentous structures are unable to function optimally. Because the popliteus musculotendinous complex has attachments that approximate the borders of both collateral ligaments, it has the potential for providing instantaneous 3-dimensional kinesthetic feedback of both medial and lateral tibiofemoral joint compartment function. Enhanced popliteus function as a kinesthetic knee joint monitor acting in synergy with dynamic hip muscular control of femoral internal rotation and adduction, and ankle subtalar muscular control of tibial abduction-external rotation or adduction-internal rotation, may help to prevent athletic knee joint injuries and facilitate recovery during rehabilitation by assisting the primary sagittal plane dynamic knee joint stabilization provided by the quadriceps femoris, hamstrings, and gastrocnemius.

J Orthop Sports Phys Ther. 2005;35(3):165-179. doi: 10.2519/jospt.2005.1414

Key Words: knee, lateral meniscus, lower extremity

Study Design: One group; pretest, posttest design. Objective: To assess the effect of a 2-hour cheerleading practice on the anterior knee laxity, hamstring extensibility, and dynamic postural stability (preferred stance leg during vision-denied unilateral stance) of 17 nonimpaired members of a college cheerleading team (8 females, 9 males; 18-25 years old). Background: Anterior knee laxity and hamstring extensibility increase following exercise. The relationship between exercise induced anterior knee laxity, hamstring extensibility, and dynamic postural stability, however, has not been examined. Methods and Measures: Pre- and postpractice measurements were compared using paired t tests and Bonferroni's correction for multiple comparisons. A 3 x 2 analysis of variance (force level applied to the arthrometer by condition) and Tukey honest significant difference post hoc test were used to evaluate specific arthrometer force level by condition effects (P < .05). Results: Mean laxity at 133 N and hamstring extensibility increased (mean ± SD) 1.5 ± 1 mm and 3 ± 4°, respectively, following practice. Mean medial-lateral stabiliometer platform angulation (frontal plane position) moved medially following practice (2.9 ± 3°) and produced a weak correlation with increased knee laxity (r = 0.58). Hamstring extensibility did not significantly relate to stabiliometry or knee laxity variables. Conclusions: The relationship between the medially directed platform angulation and the increase in anterior knee laxity following cheerleading practice suggests a relationship between subtalar joint position and anterior cruciate ligament strain.

J Orthop Sports Phys Ther. 1999;29(8):455-462.

Key Words: anterior cruciate ligament, dynamic postural stability, fatigue

Study Design: Single group repeated measures following anterior cruciate ligament (ACL) reconstruction. Objectives: The purpose of this study was to evaluate the intrarater reliability of selected clinical outcome measures in patients having ACL reconstruction. Background: Several investigations have reported the reliability of isokinetic testing and knee ligament arthrometry. Fewer studies have examined the reliability of lower extremity functional tests, with most of these studies evaluating normal subjects. Methods and Measures: Fifteen physically active males with unilateral ACL-reconstructed knees were evaluated with the KT-1000, Biodex isokinetic dynamometer, and 3 functional hop tests on 5 occasions. Results: lntraclass correlation coefficients (ICCs) revealed good to high intrarater reliability (ICC >0.80) of the functional hop tests and isokinetic peak torque values. ICCs were higher for the involved limb than the uninvolved limb using the scores from the KT-1000 Manual Maximum Test. Conclusions: The outcome measures examined in this investigation have been shown to be reliable in patients with ACL reconstructions and support previous investigations in nonimpaired populations. Further research is needed to examine the validity of these postoperative outcome measures in patients with ACL reconstructions.

J Orthop Sports Phys Ther. 1999;29(1):39-48.

Key Words: functional outcomes measures, functional testing

This study attempted to determine the effect of eccentric quadriceps femoris, hamstring, and placebo fatigue on stance limb dynamics during the plant-and-cut phase of a crossover cut. Twenty female college students (task trained) were tested. Hamstring fatigue resulted in decreased peak impact knee flexion moments (p = .01), increased internal tibial rotation at peak knee flexion (p = .05), and decreased peak ankle dorsiflexion (p = .05). Quadriceps fatigue resulted in increased peak ankle dorsiflexion moments (p < .01), decreased peak posterior braking forces (p = .01), decreased peak knee extension moments (p = .01), delayed peak knee flexion (p = .01), delayed peak propulsive forces (p < .01), and delayed subtalar peak inversion moments (p = .05). Fatigue of either muscle group produced earlier peak ankle plantar flexion moments (p = .05) and decreased peak propulsive knee flexion moments (p = .05). Variables requiring further study (p = .1) provide discussion data. Soleus, gastrocnemius, tibialis anterior, and deep posterior compartment calf muscles serve as dynamic impact force attenuators, compensating for fatigued proximal muscles.

J Orthop Sports Phys Ther. 1997;25(3):171-184.

Key Words: women, muscle, fatigue, compensatory dynamics

Injury to the distal tibiofibular syndesmosis (DTFS) may be more common than previously reported. This injury is typically caused by external forces, which produce sudden ankle dorsiflexion or plantar flexion in combination with external rotation of the foot. Common mechanisms include direct contact with another player or uneven physical terrain. Improper diagnosis of this injury may greatly delay the return to normal functional status and promote the development of chronic instability, degenerative joint changes, and pain. The purpose of this clinical commentary is to review the ligamentous anatomy of the ankle and the incidence of injury to the lateral ligaments of the ankle, with emphasis on DTFS injury. Special tests that enhance the recognition of DTFS injury, such as the external rotation stress test and the distal tibiofibular compression test, and a rehabilitation progression are presented.

J Orthop Sports Phys Ther. 1995;21(4):197-205.

Key Words: ankle, anatomy, rehabilitation

Understanding the afferent neural system of the knee is considered to be vital to rehabilitation planning. An intricate relationship exists involving the afferent neural receptors in the inert and contractile tissues of the knee. Traditional rehabilitation strategies may not exploit this extensive afferent neural system. Closed kinetic chain functional training (CKCFT) may provide a method for more effectively rehabilitating an injured or reconstructed knee. The rationale for CKCFT has traditionally focused on mechanical aspects. Sensorimotor integration through motor learning is believed to be an important component of CKCFT. The purposes of this review are to discuss: 1) the afferent neural system of the knee with emphasis on the mechanoreceptors, 2) the influence of the afferent neural system of the knee on motor learning, and 3) how CKCFT uses the afferent neural system of the knee and motor learning during knee rehabilitation. This review reinforces the use of CKCFT in knee rehabilitation plans.

J Orthop Sports Phys Ther. 1994;19(1):2-11.

Key Words: articular neurology, motor learning, knee rehabilitation