Dr. Joseph Signorile, PH.D. was our recent guest presenter for an educational webinar focused on the importance of high-speed training for older adults.
Dr. Signorile is a professor at the University of Miami in the Department of Kinesiology in the Center for Active Aging. He has been involved in research using exercise promote independence and fall prevention in older adults for over 25 years and is a pioneer in applying high-speed resistance training to improve function and reduce falls. He continues to work on new technologies and interventions for fall prevention and active, healthy aging.
During the webinar, Dr. Signorile discussed:
- The concept of power and the importance of high-speed strength training.
- Benefits of pneumatic strength training equipment
- How to incorporate power and high-speed training programs for older adults
- The positive impacts of high-speed training on Parkinson’s, metabolics and cardiovascular fitness and independence in older persons
- Supporting research from our laboratory
The following information was derived from this very important presentation.
Why is High-Speed Training important for active aging?
High-speed training has been used for decades to increase power in populations ranging from competitive athletes to older adults who want to reduce their risk of falling and minimize the loss of independence as they age.
The basis for high-speed power training is the Force-Velocity relationship which is inherent in skeletal muscle. This is represented in the Force-Velocity Curve. Power is based on an inherent property of skeletal muscle. As the velocity of a muscle contraction increases the force the muscle produces is reduced.
If you look at the graph above, you'll see that the Y axis represents Force and the X axis represents Velocity. The blue line is called the Force-Velocity Curve.
Note that the Force-Velocity Curve shows that at maximum force, velocity is zero and at maximum velocity, force is zero. The red line represents the power curve. Notice that power happens somewhere in the middle of the Force-Velocity Curve because power is the product of force and velocity.
Resistance training is typically about manipulating the load.
The change of load dictates the velocity of the exercise. This is represented in the Load-Velocity Curve, which represents using load to dictate velocity.
For example, if you had in front of you a stack of weights that was too heavy to move, the weight of the load would dictate zero velocity. As we lower the weight of the load, your ability to move the load increase, thereby increasing velocity.
As you can see from the graph above, somewhere in the middle of the Load-Velocity Curve is the opportunity to maximize power.
Why is power important as it relates to aging?
As we age, we lose muscle fibers and the muscle fibers we manage to retain shrink in size.
The graph below represents both muscle fiber size and the number of fibers present. As you can see, throughout our 20’s, 30’s, and into our 40’s, the number of fibers and the fiber size remains fairly consistent. But, in our 50’s, there is a drop, and once the decline begins, it increases exponentially as we continue to age.
Perhaps even more important, is that the fibers that are most affected by aging are Type II fibers, Type II Fibers are the faster contracting fibers and are represented in red on the graph below.
As we age, we not only get weaker from the number of fibers and the reduction of cross sectional area of those fibers, we also lose velocity of movement. In other words, we get slower.
Since force times velocity equals power, reductions in both force production and velocity of movement, equals a loss of POWER.
How much does power change as we age?
A 1994 study (Skelton et al.) found that between the ages of 65 and 89, explosive lower limb extensor power declines 3.5% per year compared to 1-2% per year decrease in strength.
Another study found that in elderly males, maximal anaerobic power declines 8.3% from the age of 20 until the age of 70. (Bonnefoy et al. 1988)
Two other studies, in their attempt to understand the elements that determine maximum power, found that the most important factor for older adults is speed of movement. (De Vito et al., 1998, and Herman et al., 2005)
Several other studies have concluded that power is one of the major performance variables associated with independence, fall prevention, and rehabilitation following injury.
The HUR SmartTouch Power Training Feature
HUR SmartTouch equipped strength training equipment includes a power training feature that makes training for power clear and simple.
Power output displayed for each repetition.This is very important because as exercisers are moving through their workout and working towards completing a set number of repetitions, they can have a goal of trying to maintain power because they can watch how power changes across the entire set.
Side-specific data and shows bilateral strength imbalances.This allows us to examine whether or not there are bi-lateral differences in both strength and power. This allows us to give a training program that might address power more on one side than the other if a discrepancy is found.
Baseline goal, target display. Baseline goals can be predetermined and programmed into the system. The target is displayed on the touch screen so individual users can see it easily.
Tracks compliance.This is important because while fitness instructors can set up a program for their clients, if the person doesn’t follow it, the plan is useless.
Auto-progression.Once the program is set up, the individual can train independently, and the level of resistance and number of reps will automatically increase as they gain power and strength.
How to Maximize Power with Strength Training Programs for Older Adults
Since Power is the product of force times velocity, if we train at the load end of the curve we cannot maximize power because even though load might be high, the velocity is too low.
Likewise, if we shift over to the velocity end of the curve, so that load is low but velocity is high, we still cannot maximize power output because load is too low.
While it varies from person to person, it’s in that mid-range between velocity and load that allows us to train for increases in power.
Standing up out of a chair requires us to move against gravity. Climbing stairs also requires us to move against gravity. Walking – the only movement against gravity is the undulation of our center as it moves. Getting out of bed also requires us to move against gravity.
Targeted Load for Functional Performance
For older adults, the best training plans are based on the results they want to achieve. This means that the training prescription should reflect the daily activities that each individual wants to target by matching the amount of load against gravity that the activity requires.
In the graph below, the yellow bar represents the amount of load and velocity that will maximize power output. If we shift training towards the right of the graph, you can see that we are training for activities that require gait velocity. On the other side of the graph, we are training for activities that require us to move load against gravity.
Supporting Research for High-Speed Training
Parkinson’s Disease. A 2016 study (Niet.al.) found that for patients with Parkinson’s Disease, Power training can reduce motor symptoms, improve balance function and gait, and increase leg muscle strength and power. And, a 2017 study (Ni & Signorile) found that power training can shift the load-velocity and load-power curves towards the velocity end of the curve in Parkinson’s patients.
Metabolic and Cardiovascular Fitness. High velocity circuit resistance training can maximize caloric expenditure and improve markers of metabolic syndrome. (Robertson et. Al.)
Functional Training. A 2014 study (Balachandran et. al.) found that high-speed pneumatic training can improve physical function in sarcopenic obese adults. Another study, published in 2018 (Buscard et.al.), found that high-speed training can improve strength, power and functional performance using linear and non-linear periodization.
Additional research has shown that circuit resistance training using explosive movements produces significantly higher power than controlled speed training in most exercises.
Cognition. A 2018 study (Cherup et.al) found that high-velocity circuit training is superior to treadmill training in improving cognition. A 2015 study (Strassnig et.al) showed that high-velocity circuit training can improve symptoms, cognition, and neuromuscular function in overweight persons with severe mental illness.
The Importance of Pneumatic Strength Training
Pneumatic strength training equipment is ideal for older adults because it eliminates many of the problems included in traditional weight stack machines.
1. The problem of inertia. The greatest problem involved with high-speed resistance training using traditional weight-stacking machine is inertia. As the user moves the weight, it develops momentum at the beginning and end of the movement, losing momentum in the middle of the move.
This creates a loading and unloading problem and a need to decelerate the weight early in the range of motion to reduce the potential for injury. This is not the case for pneumatic strength training machines.
2. Loading throughout the natural length-tension curve. Pneumatic resistance allows uninterrupted movement thorough the entire range of motion. This is in contrast to weight-stacking machines which show interrupted loading patterns throughout each movement.
3. Minimal Loads can be too heavy for older adults. In traditional weight-stacking machines there is minimal resistance load that is dictated by the weight of the plate. For many older adults, that minimal load is too much for safe training. Pneumatic machines offer a continuous resistance variable with zero starting load and very small increases in resistance.
HUR Strength Training Equipment
HUR Strength Training Equipment includes all the benefits of pneumatics PLUS HUR SmartTouch technology.
With one swipe of a wrist band, the machine will automatically adjust to the individual for maximal biomechanical efficiency. This functionality allows for safe, independent use, freeing up the time of the trainer. Once the trainer sets the parameters for each individual, the machine will automatically adjust to those parameters.