Crossfit Endurance 17th May: 400m sprints

17 May

The Crossfit Endurance class met this Tuesday for another session of skill drills and intense interval running. This turned out to be just Ruairi, who bravely faced the prospect of running in Bethnal Green in the rain. Luckily we were spared a drenching.

There are several forces acting on the body when running: Gravity; Ground Reaction; Muscle contraction; Torque; Momentum/Inertia and, the focus of today’s class, Muscle Elasticity.

Muscle elasticity is very difficult to quantify but what we should be able to observe is a marked improvement in the ability of our athletes to maintain a high cadence, which will signify greater mechanical efficiency. Stride frequency/Cadence is critical in order to allow these forces to provide maximal benefit (stride cadence should never be below 90 beats per minute). Cadence (number of pulls of one foot each minute) and stride length will increase as speed increases.

After a short warm-up, we called upon that old and dear friend the jump rope. After disposing of our trainers and going barefoot we skipped for 3×1 minute intervals on the balls of both feet, then 2×1 minute on each foot individually. In order to emphasise the importance of maintaining at least a 90 cadence, we had the monitor running while we skipped.


Then we went through a short drill of jumping up onto a box, jumping off and allowing muscle elasticity to propel us onto the next box. These drills seem straightforward and easy but they can lead to very sore calves so be careful if trying at home!

Finally we placed one foot on a box, replicating the running pose and then really focusing on using the hamstring to pull the other foot off the floor towards the bum (the technical term), and using muscle elasticity to bounce.

After these drills we performed several rounds of ball of foot hops, single leg pulls and then proper running before moving out to the park for the chewy, tasty core of the Crossfit Endurance class, the interval runs.

Ruari ran 4×400 m intervals with 2 minutes rest in between, with the goal of using proper technique and to maintain pace and form over the 4 runs. He managed to average 1:15 over 4 rounds, with very little deviation and good technique. Well done Ruairi!

As Stretch and i accumulate more data over various distances, we will be able to extrapolate performance over longer distances such as 5k and 10k. So if you would like an idea of how you would perform on race day, join us for one of the sessions to start building up your data base.

5 thoughts on “Crossfit Endurance 17th May: 400m sprints

  1. Cheers Efe – really enjoyed the session, hopefully we’ll get a few more fellow CF’s to share the pain next week.

  2. 4 x 400m, my absolute favourite…says the guy who couldn’t make it!

  3. Nice job Efe. Pic’s look awesome and I’m sure Ruairi enjoyed the personal attention (pressure to perform).

    Andrew – time to toughen the F%^& up mate… face your goat and suck less… lol

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