Warning: Reading this blog post may negatively impact your leaderboard ranking (but improve your fitness outcomes)
Fast twitch muscle fibre, it’s what makes you explosive and athletic. It is also the type of muscle fibre you lose first as you age accounting for a great proportion of the sarcopenia (muscle wasting) we observe in ageing populations. Because muscle mass is inversely associated with all cause mortality, if you want to remain healthy and active into your later years you want to prioritize maintaining your muscle mass. And that means maintaining fast twitch muscle fibres.
How do you do this? First, eat lots of protein. More on this in an upcoming blog post. Short version: probably much more than you are eating right now. At least 1 gram of protein per pound of bodyweight. Second, practice explosive movements that require fast twitch muscle fibre activation. These are movements in the sub 10-30 second range or less.
Unfortunately, there is a trend in ageing athletes to favour long, slow endurance activities precisely because with the decline in fast twitch muscle fibre, they find that they can remain competitive in endurance based athletic events whereas they cannot compete as effectively with younger athletes in sports that require speed and power.
In life, it is generally not a bad strategy to play to your strengths but, in fitness, the opposite is true. Life will punish you where you are weakest. Elderly people do not frequently meet their end as a result of lack of endurance. It is the short fall to a broken hip that kills you. An injury that you might have been able to prevent had you reacted quickly enough to catch yourself before you fell.
Box jumps and burpees, done correctly are an amazing way to train and preserve fast twitch muscle fibre. But only if you perform them as they were meant to be done: explosively. The key here is that fast twitch muscle fibre is developed in that 10-30 second effort range and is generally optimized with a work to rest ratio higher than 1:3. That is, if you work for 10 seconds you need to rest at least 30 seconds, maybe more, before performing your next work set.
Fast twitch muscle is developed in short high intensity bursts of effort at low volume. Unfortunately 10 minutes is deep into the slow twitch endurance zone and high volume burpees and box jumps completely lose their utility when done in an endurance format.
So what should you do with today’s 10 min AMRAP of Burpee Box Jump Overs?
The sport of CrossFit prioritizes the leaderboard over health so if you want the high score, by all means, switch into low gear and grind out 10 minutes of low intensity burpee box jump overs. If, however, you want to prioritize the preservation of fast twitch muscle fibre, I recommend adopting an EMOM approach.
HeeHee and I did this WOD by Shannon Falls outside Squamish jumping over a log in the forest. I chose 4 burpee log jump overs per minute and executed them as quickly as I could with correct form. The first round took me 13 seconds as I familiarized myself with the uneven terrain but I quickly brought my time down to 10 seconds per set. The game thereafter is to retain the same exact form and speed throughout all 10 rounds, never slowing and never sacrificing form. This provided me with a 1:5 work to rest ratio (10 seconds burpee log jump overs, 50 seconds rest) and by timing each set I was able to make sure I maintained the same explosive speed throughout. Though 40 reps is a rather low volume, because of the high intensity (they were completed in about 1 minute and 43 seconds worth of working time) we really felt the stimulus. Our legs were trembling and our nervous systems fired up. We got the full benefits of the neuroendocrine cascade that follows high intensity exercise without the prolonged, life-sucking fatigue associated with high volume training. In other words, we got a great hormonal hit but after walking off our rubbery legs, we still had energy to go out and enjoy our day.
The benefit of the burpee is that it is a full body movement engaging all the muscles and joints in your body and it moves a large load (your whole body) a long distance (to the ground and back up again) quickly (but only if you do them explosively as intended).
The benefits of jumping are greatly underappreciated. Besides stimulating fast twitch muscle fibre (without which jumping is not possible), the impact forces of jumping and landing are critical to preventing loss of bone density which is especially critical to ageing populations. It strengthens joints including tendons and ligaments. It stimulates the viscera and organs. It stimulates the lymph thereby strengthening your immune system. It develops the vestibular system (balance). Lose the ability to jump and you are headed to an accelerated decline in health and longevity.
To adapt my favourite George Bernard Shaw quote: “You don’t stop jumping because you grow old, you grow old because you stop jumping.”
That is why I will strongly encourage you to jump in today’s workout. You do not need to jump over the 20/24 inch box to get the benefits of jumping. Choose a 6 inch green box if it is safer for you or even a 15lb plate. If these seem too dangerous, pick a line on the floor and hop over it after each burpee rep. If you use the EMOM format and focus on quick sets that last less than 10 seconds (2 to 6 reps per minute for most of us) you will keep the volume low reaping all the benefits of jumping with minimal risk of high volume overuse injury.
Our warm up today will be long with the intention of warming up and preparing all the joints in your body for some impact forces. We will also take time in the lesson to review the anatomy of a burpee to help those of you who have forgotten how the movement is supposed to be performed. We will go over the basic 6 step burpee for beginners and the 4 step burpee for more advanced athletes. Excellence in execution eliminates injury risk and, once you develop proficiency, increases your speed. But until your movement mechanics are dialled in, speed is not your friend. Master the movement. Speed will follow.
|10/10 Head Figure 8’s CW/CCW
|10 Head Extend & Retract
|10/10 Alt Reverse Shoulder Shrugs & Rolls CW/CCW
|10/10 Arm Circles CW/CCW
|10 Arm Overhead Raises
|10/10 Double Diagonal Arm Mills
|10/10 Alt Arm Up/Down Reach
|10/10 Elbow Rotations CW/CCW
|10 each Wrist Rotations CW/CCW/Flex & Extend/Handshake Flex & Extend/Finger Squeezes
|10 each Chest Flex & Extend with breathing/Thoracic Side Shift/Side Bends/Core Rotations CW/CCW
|10 each Hip Rotations CW/CCW/Pelvic Tilt Side to Side/Forward Back/Salsa Hips CW/CCW
|10 each Standing Hip External & Internal Rotations CW/CCW
|10 Good Morning Hip Hinge
|10 each Knee Circles CW/CCW/Wide Stance CW/CCW Circles opposite legs
|10 each Hamstring behind back raises
|10/10 Alt calf raise walk
|10 each Ankle Circles CW/CCW
|10 each Toe Flex & Extend
10 Ground Sweeping Lunges
10 Side Turning Lunges
10 Turning Squat Jump
10 Forward/Backward Mountain Thrusters
3 Point Mountain Thruster
|1. Plant Hands
2. Kick Back Both Feet
3. Chest to Floor
4. Push Off Floor
5. Jump Up Both Feet
6. Jump (Over Box)
|1. Plant Hands
2. Kick Back Both Feet (Chest to Floor)
3. (Push Off Floor) Jump Up Both Feet
4. Jump (Over Box)
10 min AMRAP
Burpee Box Jump Overs
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