Mobility vs Flexibility

Flexibility is the range of motion available at a joint. You usually test and train it passively: gravity, a partner, a strap or your other hand takes the joint toward end range while the target muscles relax (see Passive Stretching, Range of Motion (ROM)).

Mobility, as Fysiqal uses the word, is active, controlled range. It is the part of that range you can reach and hold with your own muscle force and coordination (see Motor Control and Motor Learning). Active range is usually smaller than passive range. Someone can be pushed into a deep hamstring stretch yet be unable to lift that leg as high on their own. The gap between the two is what mobility work targets.

What the evidence says about building range:

• Stretching works, but acute gains are short. In Behm et al.'s 2016 review, static, dynamic and PNF stretching all increased range of motion. The immediate gain typically lasted under 30 minutes. Lasting change comes from doing it regularly. The authors attribute much of the change to reduced stiffness and greater stretch tolerance, not only longer tissue.
• Strength training through full range builds range too. Afonso et al. (2021) pooled 11 randomised trials (452 people) and found no difference in range-of-motion gains between strength training and stretching. That held for active and passive range.
• ACSM's dose for flexibility: flexibility exercises for each major muscle–tendon group, about 60 seconds total per exercise, on at least 2 days a week. ACSM also recommends neuromotor training (balance, agility, coordination) 2–3 days a week (Garber et al. 2011).

What that means in practice. Use stretching (see Static Stretching) when passive range is the limit. Use controlled, loaded work through range when control is the limit: controlled articular rotations (Controlled Articular Rotations (CARs)), end-range holds, and full-range lifts. Most people benefit from a mix.

• Lifters who can get into a position with help but not on their own: a deep squat, an overhead lockout, a hip hinge with a flat back.
• Anyone choosing between "more stretching" and "more strength work" to improve range.
• People who want a simple weekly dose rather than an open-ended routine.

• The terms aren't standardised. Research mostly measures "range of motion" (active or passive). "Mobility" as active, controlled range is a useful coaching definition, not a formal scientific one.
• More range is not always better. Hypermobile people usually need control and strength, not more stretching.
• Pain is not a mobility problem to self-treat. Joint pain, a recent injury, numbness or a sudden loss of range needs a clinician.
• Afonso 2021 found the pooled studies very heterogeneous, so "strength = stretching for range" is a group-level result.

Jordan can't reach parallel in the squat without his heels lifting.

1. Test passive vs active. In a half-kneeling knee-to-wall ankle test (shown in the Fysiqal media library as Ankle Mobility Drill (Knee-to-Wall Dorsiflexion)), his knee travels well past his toes when he leans his bodyweight in. So passive ankle range is fine. In the squat, he collapses forward at the bottom. The limit is control at depth, not tissue length.
2. Plan (3 sessions a week, ~10 minutes):
   • Goblet squat to a box, pausing 3 seconds at the bottom (a demo is in the Fysiqal media library under Goblet Squat and Box Squat). Lower the box 2–3 cm every week or two.
   • Controlled ankle and hip rotations as part of the warm-up (Controlled Articular Rotations (CARs)).
3. Keep a stretch where it helps. Static calf stretching after training, 60 seconds total per side, because tight calves are not his main issue but it's cheap to keep.
4. Re-test after 4–6 weeks: depth with heels down, in a squat he controls.

Next lesson: Dynamic Warm-Up (Mobility-as-Training). See how to turn mobility work into a 5–10 minute warm-up you'll actually do.

• Flexibility = available range (often passive). Mobility = range you can actively reach and control.
• Stretching raises range, but acute gains usually fade within ~30 minutes (Behm 2016); consistency builds lasting range.
• Strength training through full range improved range as much as stretching across 11 RCTs (Afonso 2021).
• ACSM: flexibility work ~60 s total per exercise on ≥2 days/week; neuromotor training 2–3 days/week (Garber 2011).
• Diagnose the gap first: passive limit → stretch more; control limit → strengthen at end range.