An athlete holds a dumbbell at shoulder height, pushes it straight up overhead until their arm is fully extended, holds it for two seconds at the top, and then slowly lowers it back down to shoulder level.
Prompt Questions
- Muscle Roles & Biomechanics (Chapter 10)Identify the prime mover (agonist) at the shoulder during the upward pushing phase. What class of lever (1st, 2nd, or 3rd) is operating at the elbow joint during extension?
- Types of Muscle Contractions (Chapter 9)Identify the specific type of muscle contraction (concentric, eccentric, or isometric) occurring in the primary shoulder and arm muscles during:
- The upward pushing phase
- The 2-second hold at the top
- The downward lowering phase(Hint: Is the antagonist muscle actively pulling the weight down, or is something else happening?)
- Metabolism & Fiber Recruitment (Chapter 9)If the athlete performs a heavy 3-repetition maximum (3-RM) press versus a light 30-repetition endurance set, which fiber type (Fast Glycolytic vs. Slow Oxidative) and energy pathway (Anaerobic vs. Aerobic) dominate during the heavy 3-RM lift?
Student Reply Instructions
- Initial Post: Answer all three questions in 150–250 words.
- Peer Response: Reply to at least one classmate. Identify one synergist or fixator muscle (e.g., rotator cuff muscles, trapezius, or serratus anterior) that helps stabilize the joint during this movement, and briefly state its role.