Val Burke & Co. Peak Endurance Wanaka.

Interesting study with limitations. We use both leg extension and leg press in our training groups, as well as various squats, split squats and single leg squats…We’ve got you covered! 💪🏼🏃🏻‍♀️⛷️🚴🏻⛰️

Leg press does not train the whole thigh, and leg extensions do not train the hip. Twelve weeks of MRI scans showed which muscles each machine left out.

Kinosh*ta and colleagues (Med Sci Sports Exerc 2026) had 17 untrained adults, 11 men and 6 women, train one leg on the leg press and the other on the leg extension machine, five sets of ten at 70 percent of maximum, twice a week for twelve weeks. Because both legs belonged to the same person, diet, sleep and genetics were identical, and MRI measured the volume of 17 hip and thigh muscles before and after.

The re**us femoris, the strip of quadriceps running down the centre of the front thigh, is the one quad muscle that also crosses the hip, where it works as a hip flexor. A leg press extends the hip and the knee together, so a muscle that pulls the hip the other way is fighting the movement and the nervous system turns it down, which the study
confirmed by recording its electrical activity.

Cyclists show the same pattern, with large single-joint thigh muscles and a re**us femoris no bigger than in people who do not train (Ema et al., Scand J Med Sci Sports 2016).

Across all 17 muscles, leg press added 292 cubic centimetres of muscle, a little over a cupful, against 127 for leg extensions, about half a cup. Most of that extra came from the hip: the gluteus maximus grew 15 percent and the adductor magnus on the inner thigh 6 percent on leg press, and neither moved on leg extensions. The three vasti, the bulk of the quadriceps, grew 5 to 7 percent on either machine. The re**us femoris grew 13 percent on leg extensions and 1 percent on leg press, a change indistinguishable from zero. Ten weeks of squats give a similar map: knee extensors up about 5 percent, glutes up, re**us femoris unchanged (Kubo et al., Eur J Appl Physiol 2019).

Seventeen people is a small trial:

whole-quadriceps growth of 7.1 percent on leg extensions against 4.9 on leg press was not a significant difference, so the two may or may not differ there. Legs were assigned by dominance rather than at random. Everyone was untrained, and beginners grow from almost any stimulus, so the gaps could change in experienced lifters. Both exercises used machines at a fixed seat angle, and a free-weight squat or a different backrest setting changes how far the hip bends and could change what the re**us femoris does.

The scans describe a division of labour rather than a winner. Leg press covered the hip, the inner thigh and most of the quadriceps in one movement and added more than twice the total muscle, while leg extensions were the only one of the two to reach the re**us femoris, a muscle that matters for sprinting and kicking. A programme built on one machine alone leaves a measurable muscle untrained, and the scans show which one.

Kinosh*ta et al., Med Sci Sports Exerc 2026;58(7):1566 · PMID 41630124
Ema et al., Scand J Med Sci Sports 2016;26(7):782 · PMID 26148051
Kubo et al., Eur J Appl Physiol 2019;119(9):1933 · PMID 31230110

Hey Swimmers!
Now is the time to begin building your fitness base and technique for your summer swimming goals.

Squads start back next week (from 27 July).
We have spaces in sessions Thursday morning (Women) and Tuesday & Thursday evenings.

1:1 technique & lessons are a great way to dive deep into how to swim more efficiently.

Details: https://valburke.com/peak-endurance-swimming/

Inquiries to: [email protected]

I agree 100% with Ruth Croft, and am so glad she’s spoken up!!

Before I left NZ a few weeks ago, I heard more conversations around teenagers competing in ultras and endurance events, and it’s something that’s been sitting with me since. And maybe this isn’t something that we are seeing just in NZ…

Ultras have always existed, but over the last few years they’ve become far more visible, popular, and celebrated. A lot of the messaging around them revolves around suffering, pushing through pain, and constantly testing your limits - and there is pride in that, and that mindset is often praised.

By no means am I saying teenagers shouldn’t challenge themselves, and I’m definitely not trying to gatekeep endurance sport.

I honestly understand the draw. When I was younger, I was always the kid who wanted to do more too. But the pathway looked very different then. It was track, cross country, mountain running, and road relays — all through the club system.

There was progression, variety, and time to slowly develop. I didn’t run my first ultra until I was 24.

As adolescents, you aren’t a finished product yet. Growth plates are still open, hormones and endocrine function are still developing, and for many young people it’s already a time when body image and identity can become complicated. Adding the physical and psychological demands of ultra-endurance sport on top of that is something I think we need to approach carefully.

For me, being young in sport should be about building a foundation grounded in the joy of movement, developing technique, speed, and a healthy relationship with training.

As adults, whether we’re coaches, parents, race organisers, or mentors - it’s on us to make decisions that prioritise long-term health over short-term achievement.

Because the goal isn’t just to see how far they can go now- it’s to make sure they’re still running, healthy, and happy years down the line, and that they have a body that enables them to do just that.

This theory is one of the reasons I recommend runners try to run 1-2 x/10 days for as little as 30 mins during their off season or mid season training break. It’s also one of the reasons that we need to progressively build up load after a full break such as injury where you’ve not been able to load your tendons, bones etc. there is much more to take into consideration than simply “run fitness”, and one of the biggest causes of injury is “pre existing injury”, followed by p**s poor rehab x too much run overload! It’s a science and an art!

Tendons respond to load. Most people already know this intuitively. What many do not realize is that tendons respond very poorly to prolonged rest, especially the kind of rest that leads to deconditioning from avoiding movement entirely.

This is one of the most consistent findings in tendon biology research, and yet it remains one of the most misunderstood concepts in everyday practice.

Complete rest weakens tendons.

Appropriate loading does the opposite. It stimulates collagen synthesis, improves tendon organization, and gradually rebuilds the tissue capacity needed to tolerate daily life and exercise again. Tendons heal through progressive loading, not through being completely protected from movement forever.

And yet, many people immediately strap, brace, or immobilize the area because they are afraid something serious is happening or worried they will make it worse. Sometimes temporary support is necessary if symptoms are severe, but prolonged avoidance often creates a different problem: the tendon becomes less capable of handling stress once normal activity returns.

In many cases, the tendon heals better when it continues moving and receives the right amount of progressive load.

I go much deeper into tendon rehab, loading principles, pain science, and evidence-based recovery strategies on my subscriber page. If you want the full discussion and practical guidance, the link is in the comments.

Ever feel like you’re working way too hard in the water… and still not going very fast?

I’m opening a small freestyle swim group for people who can swim, but know there’s a better, easier way.

This is about:
✔ Improving technique
✔ Using less energy
✔ Building confidence

Spots are limited. Reach out if this sounds like you: [email protected]

Tuesdays 7:30pm. 7 weeks from 19 May - 30 June.

Ladies! Do you need more swimming in your life?

There are highly sought after spaces in the Peak Endurance Women's Squad for this term.

✅ Improve your technique
✅ Learn new skills
✅ Make new connections

Thursdays 8:00 - 9:00am through till 4 July.

Contact [email protected] for details and pre-requisites.