Muscle: Force - Velocity

What is the main purpose of the practical?

To identify the force-velocity and force-power relationships of skeletal muscle.

What variable is changed in the method to study muscle performance?

The external resistance on the cycle ergometer flywheel.

What is observed when external resistance is changed?

Pedal cadence and power output.

How is resistance applied to the flywheel determined?

It is calculated as 7.5% of body mass.

What are the key warm-up steps in the protocol?

3 minutes at 100W, a 5-second sprint, then 2 more minutes at 100W.

How many sprints are performed in the test, and how long are they?

4 maximal sprints, each lasting 6 seconds, with varying resistance.

What is the post-sprint recovery protocol?

1 minute cycling at 60 rpm, followed by 4 minutes of rest.

What data is collected during each 6s sprint?

Total pedal revolutions, External load (kg) converted to force (N), Power output and power per kg body weight.

What is the formula to calculate force in Newtons?

Force = mass (kg) × 9.81 N/kg.

What is the formula to calculate power?

Power = Work / Time, where Work = Force × Distance.

What is the shape of the force-velocity relationship?

Inverse relationship – as force increases, velocity decreases.

What does a high force correspond to in terms of velocity?

Low velocity.

What should the force-velocity graph look like?

A downward slope from left to right.

Why do higher loads cause slower contraction speeds?

Because muscles must generate greater force, which takes more time.

What should the F-V regression equation represent?

The relationship between external force (N) and velocity (cadence).

How is power calculated?

Power = Force × Velocity.

What happens to power as velocity increases?

Power increases to a peak, then decreases as velocity keeps rising.

What shape is expected in a power-velocity graph?

A bell-shaped curve.

Why do sprinters reach peak power at higher velocities?

Because they rely more on fast-twitch fibers than marathon runners.

How does strength training affect the P-V relationship?

It shifts the curve to the right, indicating higher peak power and optimal velocity.

When is power typically maximized in the F-P relationship?

At a moderate resistance (intermediate load).

Why is power lower at very low or very high force levels?

Because those extremes are less effective for generating power.

Where does peak power occur in the F-P graph?

At a specific intermediate load.

What do you do with your F-V data?

Fit it to a regression model (linear or polynomial) to analyze the relationship.

How do you determine the optimized peak power value?

Identify the force and velocity combination that produces the highest power output.

What is needed in the physiological explanation of the graphs?

A discussion of muscle fiber types and skeletal muscle mechanics (e.g., contraction speed, force generation).