How Training Tendons Makes You Stronger Than Big Guys

Summary

The video presents isometric tendon training as a way to build strength without necessarily adding much muscle mass. It describes a 12-week study in which participants’ tendon stiffness and strength increased substantially, while muscle growth was comparatively small.

The main principle is to hold against a challenging load for long enough.

Exercises

Wall sit

Slide down the wall until your thighs are roughly parallel to the floor. Complete 4 holds of 20–45 seconds, resting about a minute between sets. When 45 seconds feels manageable, add a heavy backpack or try a single-leg version.

Calf hold

Stand on one foot on a step, rise onto your toes, lower partway, and hold for 20–30 seconds. Complete 4 sets per leg, using a wall for balance. Add a backpack when the exercise feels easy.

Doorframe push and pull

At chest height, push against the frame as if trying to move the wall, then pull against it. Use about 7/10 effort and hold each effort for around 20 seconds.

Towel pull

Stand on a towel, hold both ends, and pull upward as if trying to lift the floor. Keep your back straight. The towel stays still, but the effort loads your muscles and tendons.

Hang

Hang from a bar with straight arms for 4 holds of 20–30 seconds. If needed, keep your feet on the ground to reduce the load. Progress to hanging from a towel only when regular hangs feel manageable.

Training Principles and Plan

• Train 3–4 days a week for about 10–15 minutes. The video suggests four sets per exercise, generally holding for 20–45 seconds.
• Make each hold challenging—around 7/10 effort, with the final few seconds feeling difficult. Use a timer, since hard holds can feel longer than they are.
• Tendon training depends on both sufficient duration and sufficient load. Short, rapid contractions or very light effort may not provide the same tendon stimulus.
• Continue regular strength training, such as push-ups and squats. The video presents tendon holds as a complement, not a replacement.
• Increase difficulty gradually, and only when the current version feels manageable.

What to Expect and Safety

Hold times may improve quickly at first, largely because your nervous system is learning to use your existing muscles more effectively. Tendon changes take longer; the video recommends giving the plan about 12 weeks before judging its effects.

Breathe throughout each hold. Stop if you feel joint pain, rather than ordinary muscle burning. If you’re under 18, keep the load moderate and avoid adding extra weight.

The video offers this informal wall-sit scale:

• Under 30 seconds: Work on wall sits.
• 30–60 seconds: An average result.
• 1–2 minutes: A solid result; consider progressing to a single-leg version.
• Over 2 minutes: Focus more on hangs and towel pulls.

The video cautions that this scale is not a medical or fitness assessment. Track your wall-sit time, check again in four weeks, and use the full 12-week period to assess longer-term progress.

Presenter and Sources

Presenter/source: The Rep Theory channel; no individual presenter is identified in the subtitles.

Research cited:

• Kubo et al. (2001), Journal of Applied Physiology
• Kubo et al. (2001), The Journal of Physiology
• Arampatzis et al. (2007), Journal of Experimental Biology
• Bohm et al. (2015), Sports Medicine – Open
• Moritani & deVries (1979), American Journal of Physical Medicine