Muscle matters as we age.  It is our hope that we are entering an era where skeletal muscle gets recognized as one of, if not THE, most important organ systems of the human body when it comes to healthy aging.

 

But what qualities of muscle health matter most when it comes to healthy aging?  Muscle size?  Muscle Strength?  Flexibility?  Endurance?  Power?

 

We can argue many scenarios where each are important.

 

You probably know some seniors who stretch, have a strength training routine, or do some form of longer duration physical activity that could build some endurance.

 

But how many seniors do you know who work on training for power?

 

 

What is muscle power and why is it important as we age? 

 

Muscle power is defined as the amount of work performed per unit of time, which is the product of muscle force and velocity.  Power refers to the ability to exert force quickly, which is important for daily movements that require speed like getting up from a chair, walking quickly or catching yourself from a fall.

 

It won’t surprise you that power declines with age.  However, muscle power declines faster than muscle mass and strength during the natural aging process.  In fact it declines both earlier and fast.  Power is estimated to decline at approximately 3% per year, versus muscle strength at approximately 2% per year and muscle mass at approximately 1% per year.

 

 

 

Sarcopenia, the loss of muscle mass as we age, has widely been recognized a significant contributor to physical decline with age.  But an article published early this year in the journal Sports Medicine proposed a new term: powerpenia, the loss of muscle power as an independent risk factor for for maintaining functional independence and preventing falls.

 

Why loss of power is a greater risk of disability compared to loss of strength?

 

Strength and power are related, but different.  Power requires the use of strength quickly.  Therefore having sufficient strength does not ensure you have sufficient power.

 

And studies have shown that impairments in muscle power were more influential determinants of mobility performance (habitual gait speed, stair capacity) and functional status (ie rise from a chair) compared to muscle strength.  In fact, older adults with low muscle power had a 2-3 fold greater risk of significant mobility impairments compared to individuals with low muscle strength.

 

Muscle contraction velocity is also associated with measures of balance that are predictive of falling.

 

This bears repeating: without sufficient power your risk of falling increases, and falls can lead to fractures that initiate a cascade of negative outcomes.

 

Muscle power output has also been found to be a risk factor for mortality, independent of muscle strength, physical activity, and muscle mass.

 

 

Is power training safe for older people?

 

 

 

Although some adverse events (e.g., minor strains and tendonitis) have been reported in older people following power training, the injury incidence is very low and not diferent compared to other training modalities.

 

 

However, in certain clinical situations the increase in speed of a movement may exacerbate the symptoms of existing clinical conditions.  Modifications or variations may be required to work around more complex circumstances such as meniscal issues, advanced arthritic conditions or tendon injuries.  This may require the guidance or recommendation of a health care professional with expertise in injury rehabilitation.

 

Despite the widespread recommendations and evidence on the effectiveness of power training  (i.e.,~300 scientific articles published in different databases on this topic in the past 10 years), some health professionals remain reluctant to implement this mode of exercise for older people for fear of injury.  This fear has permeated into current exercise guidelines that do not include information on velocity of resistance training in older adults.

 

This fear of injury, has led to a gap in knowledge and real world application.  And this has led an author group in the last year to propose a new term called powerpenia to highlight loss of power as a key biomarker of physical decline with age.

 

What age is too old for training muscular power?

 

Just like strength training, you can improve power, or at the very least minimize the natural decline at any age.

Previous studies (including meta-analyses) have shown that power training is more effective in improving functional abilities (i.e., sitto-stand, walking ability, stair climbing) than low-velocity resistance training (~14–21% vs~9–19%, respectively).

 

Training for power specifically can thus garner functional improvements beyond that of resistance training.  It is never too late to get started.

 

How do you train for power?

 

In simplistic terms, to train for power you have to incorporate speed into the repetition of movement.

 

Pick exercises or movements you are proficient and comfortable training with slow and controlled movements before working them for power.

 

Typically for a given exercise the concentric muscle action phase (shortening) should be performed as fast as possible, followed by a controlled, slower eccentric muscle action phase (lengthening).

 

Training intensity should use light to moderate resistance (between 20 and 70% of 1-RM) in order to maximize muscle power in lower limbs.

 

Training for power should avoid fatigue or failure and thus sets should have plenty of rest between them (60-120 seconds) and repetitions performed should avoid pushing towards fatigue (6-12 reps).

 

Exercises can include free weights, machines or body weight exercises (where appropriate).

 

Wishing more power to you!