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: 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

Recently, there has been attention to the clinical application of closed kinetic chain and joint isolation exercise. Our purpose was to compare the effect of joint isolation and closed kinetic chain exercise on quadriceps muscle performance and perceived function in patients with patellofemoral pain. Twenty-three patients participated in an 8-week training period and were assigned to either a closed kinetic chain or a joint isolation exercise training group. An 8-inch (20.3 cm) retro step-up test was performed at baseline, 8 weeks, and 1 year. Seated knee extension testing was measured at baseline and at 8 weeks using peak concentric torque on an isokinetic dynamometer at 90°/sec, 180°/sec, and 360°/sec. Perceived functional status was rated as excellent, good, fair, or poor based on questionnaire response. Statistical analysis showed that both groups had significant improvement in peak torque at all speeds, but only the closed kinetic chain group showed significant improvement in closed kinetic chain testing and perceived functional status. We concluded that closed kinetic chain training may be more effective than joint isolation exercise in restoring function in patients with patellofemoral dysfunction.

J Orthop Sports Phys Ther. 1996;24(3):136-141.

Key Words: muscle strength, patellofemoral pain, kinetic chain