1.3 Musculoskeletal Interventions

Interventions for musculoskeletal conditions run from passive (joint mobilization) to active (therapeutic exercise). The NPTE wants the most appropriate choice for the patient's stage of healing and presentation — and it consistently rewards active, evidence-based care over passive modalities.

Joint Mobilization

Maitland Oscillation Grades

Grades I-II modulate pain by stimulating joint mechanoreceptors (gate-control theory). Grades III-IV stretch a restricted capsule to gain ROM. Grade V thrust is a manipulation requiring advanced training and is regulated by state practice acts. A simple rule: pain dominant -> low grades; stiffness dominant -> high grades.

Mobilization Direction (Concave-Convex Rule)

To gain ROM you mobilize in the direction of the restricted glide:

• Convex moving surface (e.g., humeral head on glenoid): glide opposite the restricted bone motion. To improve shoulder flexion, apply an inferior glide.
• Concave moving surface (e.g., tibia on femur in open-chain extension): glide in the same direction as the restricted bone motion. To improve knee extension, apply an anterior glide of the tibia.

Mobilization vs. manipulation precautions/contraindications: avoid in the presence of malignancy, acute inflammation/infection, fracture, joint hypermobility/instability, ligamentous rupture, and (for cervical thrust) signs of vertebrobasilar insufficiency or upper-cervical ligament laxity. Always re-screen before high-grade or thrust techniques.

Therapeutic Exercise

Progression Continuum

1. PROM — therapist moves the joint (acute/post-op).
2. AAROM — patient initiates, therapist assists.
3. AROM — patient moves independently against gravity.
4. Isometrics — force without motion (useful when movement is painful or restricted).
5. Isotonic concentric — shortening against resistance.
6. Isotonic eccentric — lengthening against resistance (greatest force; key for tendinopathy).
7. Isokinetic — resistance accommodates effort at a fixed speed (specialized equipment).

Progressive Resistive Exercise (PRE)

DeLorme's ascending load serves as a built-in warm-up; Oxford's descending load front-loads effort before fatigue sets in. General strengthening uses moderate loads (~60-80% 1-RM, 8-12 reps); endurance uses lighter loads and higher reps; power uses higher velocity.

Soft-Tissue Techniques and PNF

PNF Diagonal Patterns

PNF uses spiral, diagonal patterns that mimic function. Upper extremity: D1 flexion = shoulder flexion/adduction/external rotation (hand to opposite shoulder); D2 flexion = shoulder flexion/abduction/external rotation (a 'draw-the-sword' reach up and out). Each has a mirror extension pattern.

PNF Stretching

Matching the Intervention to the Stage of Healing

The single most common MSK intervention question is really a timing question: given this stage, what is most appropriate? In the acute/inflammatory phase (roughly the first days) the goals are protection and pain/edema control—relative rest, gentle PROM/AAROM, isometrics, and modalities for symptom relief. In the subacute/proliferative phase, progress to AROM, light isotonics, and controlled loading to align healing tissue. In the remodeling/chronic phase, load progressively with eccentric and functional, task-specific training to restore strength, power, and return-to-activity capacity.

This staging is why two patients with the 'same' diagnosis get different answers: a day-3 ankle sprain and a six-week ankle sprain call for different interventions. The exam also rewards active over passive: when an item offers a passive modality and an equally available active exercise for a chronic MSK problem, the active, evidence-based choice is usually correct. Modalities are best framed as adjuncts that make active exercise possible (e.g., controlling pain so the patient can move), not as standalone cures.

When progressing resistance, advance only when the patient performs the current level with good form and without a symptom flare; a useful rule is to increase one variable at a time (load, volume, range, or speed) so that any symptom change is interpretable.

Patient Education as an Intervention

The NPTE treats patient education as a legitimate, often preferred intervention rather than an afterthought. Teaching activity modification, a home exercise program, pain-science reassurance for persistent pain, and self-management strategies frequently outperforms a passive modality on 'most appropriate' items, especially for chronic conditions. Effective education is specific and checked for understanding (teach-back), aligns with the patient's goals (salience), and empowers active participation—mirroring the same evidence-based, active-care philosophy that runs through the entire interventions domain.