Mitochondria are the “batteries” inside our cells that are responsible for creating energy from fuel sources such as oxygen, carbohydrates, fats, and even amino acids. These little “powerhouses” are present in nearly all cells and tissues, but are especially important for the optimal function of skeletal muscle.
The function of the mitochondria in skeletal muscle extends way beyond providing energy to the muscles that move our skeleton. They also play a key role in energy metabolism, ridding the cells of waste products, and modulating the calcium that is critical for effective muscle contraction.
Another cool thing about mitochondria is that they can adapt to the demands placed on the muscles. They can fuse and divide in response to physical demand and nutrient availability. They can also recycle old mitochondria and replace them with new and healthier ones.
When mitochondria are unhealthy, it creates all kinds of problems, including sarcopenia (muscle wasting), insulin resistance, and metabolic dysfunction, as well as inefficient removal of waste products (reactive oxygen species), which can negatively impact mitochondrial function, leading to muscle atrophy and other functional impairment.
Men and women experience an age-related decline in mitochondrial function. Interestingly, estrogen receptors are found in human muscle mitochondria, with evidence suggesting that changes in estrogen exposure to the mitochondria may affect mitochondrial function. This begs the question of whether the hormonal changes of menopause impact mitochondrial health, and research is ongoing to find the answers. To learn more about what is known about estrogen receptors and their function in mitochondria, check out this review: The Impact of Skeletal Muscle ERα on Mitochondrial Function and Metabolic Health
So what do we know for sure? Resistance training and aerobic exercise promote muscle and mitochondrial health by stimulating muscle adaptation. Adaptation comes from changes in the muscle fibers themselves and mitochondrial remodelling, where mitochondria can multiply and become more functionally efficient.
There are also supplements that may help optimize mitochondrial function:
Creatine is like the “charger” for the mitochondrial battery with adenosine tri-phosphate (ATP) as the “juice” in the battery. When there is abundant ATP, the cell has all it needs to generate energy, and creatine helps to ensure that the mitochondria are fully charged with ATP.
Here are a few references if you want to learn more about creatine:
Why Active Women Need Creatine by Dr. Stacy Sims
5 Sports Supplements for Female Athletes by Selene Yeager
The Benefits of Creatine Supplementation for Active Older Women by Yours Truly, Athletic Aging archives
Urolithin A - This is a supplement that a client of mine told me about. So I did a little digging into the literature, and it seems like there is some promise!
Urolithin A is a naturally occurring substance synthesized by the gut microbiome from the metabolism of a class of compounds called Ellagitannins. They are found in various fruits and nuts like pomegranates, raspberries, walnuts, and almonds. They promote more effective “recycling” of old mitochondria, have powerful antioxidant and anti-inflammatory properties, and promote efficient energy metabolism. It is estimated that only 40% of people have sufficient microbiota for significant urolithin A production, so there may be a benefit to supplementation.
To learn more, check out this review: Pharmacological Effects of Urolithin A and Its Role in Muscle Health and Performance: Current Knowledge and Prospects
As with all supplements, it is important to check in with your doctor or pharmacist for any potential interactions with any medications you are taking.
Now, on to today’s mitochondrial-building workout! Happy Leg-Day!
Our legs are made up of the largest bones and muscles in our body. They move our skeleton, explode with power during jumping and sprinting, and can sustain us for extended periods on long runs or biking excursions. Besides moving our skeleton, they are responsible for helping us rise from sitting to standing, ascending and descending stairs, among many other movements we hope to continue to do beyond our 8th decade of life.
When our hormones change during mid-life, muscle mass, strength, and power decline along with our bone density, particularly in the femoral neck, which is the part of the femur (the large bone of the upper leg) that articulates with our pelvic bones so that our legs are able to support our upper bodies. If muscle mass and bone density loss is severe, hip fractures and sarcopenia (muscle wasting) can cause deterioration in our ability to do even the simplest tasks, such as sitting, standing, and walking, and can dramatically impact our independence and even life-expectancy.
But this does not have to be our fate as midlife women! By taking the time to focus on our legs and train for muscle strength, stamina, and power, we can subvert these changes, continue to excel in our athletic endeavors, and remain independent and vital during our 7th, 8th, and 9th decades and beyond!
Warm-Up
AMRAP 5 minutes (As many rounds as possible in 5 minutes)
10 Jumping Jacks
10 Air Squats
Workout
Part 1 - Lift Heavy
This workout is ideally performed with a heavier barbell taking it off the rack. If you do not have a barbell and are using dumbbells, do these repetitions as 2:2:1 tempo repetitions (2 count down, hold at the bottom for a 2 count, then rise for a 1 count). All 6 repetitions should be performed unbroken, building in weight across all 5 sets.
Every 2 minutes for 5 sets
Set a timer and perform 6 repetitions on the zero and even minutes for a total of 10 minutes. Rest for the remainder of the interval after the 6 repetitions are completed.
Heavy barbell Front Squat - 6 repetitions
TIP!: “Heavy” does not mean that you sacrifice mechanics! Watch the video and maintain the strictest of form and do not compromise safety! Some wiggle-room is allowed as fatigue sets in, but it should never get ugly.
(Alternative: Dumbbell Front Squat at a 2:2:1 tempo)
Part 2 - Sprint Interval Training (SIT) and Plyometrics
Part 1 of the workout targets your fast twitch power muscle fibers. Part 2 targets your sustained slow twitch type 1 fibers while still recruiting the fibers responsible for explosive movement….and your bones, heart and lungs will thank you too!
How To: This will get spicy fast! Set your timer for Tabata 20 sec of work and 10 seconds of rest. Your goal is to accumulate 80 jumping air squats over these tabata intervals. You can expect this to take around 10 rounds. If you cannot finish, that’s ok! Save this as a benchmark and try it again in 2-4 weeks.
Tabata 20 seconds of work / 10 seconds of rest
Accumulate 80 jumping air squats
(Modification: If jumping with your feet leaving the floor is not accessible to you, try dumbbell thrusters with lighter weight - 5-10 pound dumbbells should suffice).
You’re Welcome! ;)
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HI Dixie... thanks for reading! Creatinine is a kidney function test and creatinine is a naturally occurring substance found in the muscle of animal protein. I'm not sure why your levels are elevated... you may want to check in with a provider.
-Dr. Carla
My creatine level is elevated? Why would that be ? Difference between creatine and creatinine?