Reduced force generation suggests impaired interaction between the contractile filaments. During muscle contraction, myosin heads bind to actin to form cross-bridges.

This interaction allows the myosin head to generate force and pull the actin filament, shortening the sarcomere and producing contraction.

Thus, myosin is the protein responsible for cross-bridge formation and force generation.

Exam rule: Cross-bridge formation → myosin

Why not the other options?

Troponin: This binds calcium and regulates access to actin binding sites but does not form cross-bridges.

Tropomyosin: This blocks actin binding sites at rest and moves during activation but does not form cross-bridges.

Titin: This provides elastic support within the sarcomere and does not participate in contraction.