Training at Length: The length-tension relationship

You’ve heard it lauded as the breakthrough of the century: reps at long lengths build more muscle. You might have repeated it to your mates because 'optimality'.

Long length reps are very well grounded in the current body of research and the study that had every influencer from Aachen to Zanzibar talking (Warnecke, 2023?) was a surprising application of the preexisting knowledge of a more technical concept: length-tension relationship.

I'll quickly explain. Length-tension relationship describes how when your muscle is at its mid-length, it can produce maximum force. However, too short or too long, and that force production dramatically decreases. This explains why, for example, people most fail at the bottom of a squat (both quads and glutes are stretched).

Throughout this article, I'll break down how the length-tension relationship works, why it matters for your training, and most importantly, how you can use this knowledge to design smarter workouts that produce better results.

What Is the Length-Tension Relationship?

The length-tension relationship refers to how a muscle’s ability to generate force changes depending on how stretched it is.

• At a shortened length, the muscle can't contract any more so it can't produce maximal force.
• At mid-range, the hooks (filaments) that make up the muscle fibers are able to connect and pull, generating the most force.

• Overstretched, the filaments can’t connect, and force drops again.

Take an incline curl, the kick-off is usually hard since the muscle is stretched at both the shoulder and the elbow, the mid-range strength you feel is because your muscles are at optimal length for force production and then at some point the bicep is so contracted it can’t possibly contract more so force production decreases.

Why It Matters for Hypertrophy

Hypertrophy, you'll remember, is triggered by two classical mechanisms:

• Mechanical tension, and
• Metabolic stress

(Note: I know about muscle damage. I don't currently consider it meaningful enough for inclusion). Of those, mechanical tension is your main guy.

And here’s what you want to understand about the hypertrophy connection:

When the muscle is already shortened, the joints it pulls on are maximally pulled and you have no more range of movement;

When the muscle is in its mid-range you're at your strongest already,

Only at a lengthened range do you have the force output impairment and the range of motion available to translate that into movement by creating a load of tension.

More tension = more hypertrophic stimulus.

This is supported by various studies showing that training at longer muscle lengths leads to more growth.

For example:

• Leg extensions (with the hip extended) grow more quad than seated extensions.
• Incline curls (long head of biceps in a stretched position) outperform preacher curls for growth.
• Overhead triceps work (like skull crushers or cross-body extensions) hits the long head harder than pushdowns.

Apply It in Your Training

Here's how:

Movement selection

Select movements where the muscle is under tension in its stretched position. For example:

Bear in mind, not every single exercise you do has to be lengthened. It is demanding to produce all that force, use them in combination with other exercises where you can perform well.

Manipulate Resistance Profiles

Cable machines especially, but also changing the angles on your free weight exercises can change resistance profiles of exercises. You want the hardest point of the lift to match the stretched position.

Examples:

• Use a low pulley for chest flys to challenge the bottom position.
• Anchor cables behind you during lateral raises.
• Position yourself away from the cable during curls to stretch the biceps more.

Train Through Full ROM (Range of Motion)

Long lengths are often the hardest, and often cut out by unsuspecting gym goers. Cutting ROM means cutting stimulus. Go deep. Control the bottom. Mark the bottom part of the lift.

A necessary word of wisdom.

Following this article, undoubtedly I'll see some fella on the pec deck with the grips set all the way on the last setting to max out the stretch gains. Don't be an idiot. Stretch is good, overstretching a tissue to breaking point is injurious. Avoid this.

If you're looking to get gains in an effective way, let me get you a plan that gets you gains. Get in touch for coaching.

Till next time