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  3. Exercises
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  5. Core & Abs
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  7. Roll Ball Seated Hamstrings Active

Exercise guide

Roll Ball Seated Hamstrings Active

  • Beginner
  • Isolation
  • Timed hold
  • Lower legs
  • Waist

This unilateral isolation exercise targets the hamstrings through a controlled curling motion, improving mind-muscle connection and knee stability while seated. It is an effective way to activate the posterior chain and improve knee flexion control without heavy external loading.

Reviewed by the Crucible Fit team · Updated June 2026

Watch the Roll Ball Seated Hamstrings Active demonstrationVideo and instructions for every movement are in the Crucible Fit app.

Muscles worked

Primary

  • Hamstrings

Secondary

  • Abs
  • Glutes

Equipment

  • Medicine ball

Setup

  1. Sit upright on the edge of a flat bench with your back straight and core engaged.
  2. Place a medicine ball on the floor in front of you and rest the heel of your working leg on top of it.
  3. Keep your non-working foot planted firmly on the floor for stability.
  4. Grip the sides of the bench with your hands to maintain an upright torso.

How to do it

  1. Exhale and pull the ball toward the bench by flexing your knee and digging your heel firmly into the ball.
  2. Contract your hamstring hard at the point of maximum knee flexion.
  3. Inhale and slowly roll the ball back to the starting position by extending your leg with control.
  4. Maintain a steady, rhythmic tempo, ensuring the ball does not roll side-to-side.

Form checklist

  • Keep your torso stationary; avoid leaning back or rocking your hips to move the ball.
  • Maintain constant downward pressure on the ball to keep the hamstring under tension.
  • Ensure the movement is driven entirely by the knee joint.
  • Keep your toes pointed upward (dorsiflexed) to better engage the calf and hamstring complex.

Pro tips

  • Imagine you are trying to pull the ball 'through' the floor to maximize the mind-muscle connection in the hamstring.
  • Hold the peak contraction for one second when the ball is closest to the bench to increase time under tension.

Make it harder

  • Perform the movement with your eyes closed to increase the demand on proprioception and stability.
  • Slow down the eccentric (return) phase to a 4-second count to increase muscle fiber recruitment.

Frequently asked

What muscles does the roll ball seated hamstrings active work?
The roll ball seated hamstrings active primarily targets the hamstrings, and also works the abs and glutes as secondary muscles.
What equipment do you need for the roll ball seated hamstrings active?
The roll ball seated hamstrings active uses medicine ball.
Is the roll ball seated hamstrings active good for beginners?
Yes. The roll ball seated hamstrings active is a beginner-friendly movement and a strong foundation to build on.

Related exercises

  • Alternate Hamstring Curl Sky PunchIntermediate · glutes and hamstrings
  • Alternate Single Leg Raise PlankIntermediate · abs, deltoids, hamstrings, and obliques
  • Alternating Child To Downward Dog To Body RockIntermediate · abs, calves, hamstrings, and lats
  • Alternating Hamstring Curl JackIntermediate · abs, glutes, hamstrings, and quadriceps

Train it with Crucible Fit.

Every movement in this library is in the app with video and instructions, ready for your own sessions on the days between Crucibles. Your first Crucible is on us.

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