Flexibility Guidelines (Program Standards)

Under "Standards for Exercise Program Recommendation," section II (Flexibility):

Purpose: To promote increased range of motion in the major muscle groups. The flexibility exercises improve the elasticity of muscle, as well as reduce the risk of injury during intense exercise.

Guidelines:

• a. All stretches are static in nature (see static-stretching).
• b. Stretches should be held for 10 seconds.
• c. Each stretch should be repeated twice.

The program standards also list the "X-Rated Exercises" to avoid (see x-rated-stretches-list). This flexibility section follows the warm-up section in the standards (see warm-up-aerobic-general). For the ACSM version of the guidelines, see flexibility-guidelines-acsm.

The ROM/elasticity purpose still holds, but "reduces the risk of injury" doesn't: a systematic review of 6 trials (5,100+ participants) found stretching did not decrease lower-limb soft-tissue injuries. Separately, long-duration static stretching before power/strength work can reduce force, power, and speed output (effects lasting up to an hour) — but this program's own 10-second hold sidesteps that concern entirely: current research shows holds of 60 seconds or less maintain (or only slightly affect) strength/power while ROM still improves. The prescribed duration here is fine; the injury-prevention framing is what's dated. See verification_note in this module's frontmatter.

• Purpose: promote increased ROM in major muscle groups; improve muscle elasticity; reduce injury risk during intense exercise (source's original framing — see 2026 update).
• All stretches are static in nature.
• Hold each stretch for 10 seconds.
• Repeat each stretch twice.
• 2026 update: stretching does not reduce lower-limb injury risk (large reviews found no effect); the 10-second hold prescribed here is short enough to avoid the separate power/strength-loss concern seen with long holds.

• static-stretching — the required stretch type.
• flexibility-guidelines-acsm — the ACSM guideline counterpart.
• warm-up-aerobic-general — the preceding prep section in the standards.
• x-rated-stretches-list — contraindicated stretches listed in the same standards.