You can increase your ability to sustain a given speed longer by increasing the pool of muscle fibers capable of contributing to each pedal stroke.
Cycling involves a certain type of communication between the brain and the muscles.
The brain sends electrical signals to the muscles causing them to move in the exquisitely choreographed pattern we know as the pedal stroke. The muscles, in turn, send sensory feedback to the brain, which uses this information to modify force output, cadence and so forth.
To train for cycling is to practice this special form of communication between your brain and your muscles. Such practice improves neuromuscular signaling in ways that make you a stronger cyclist.
For example, training increases the number of motor units that your brain is able to access and use to contribute to cycling. (A motor unit is a bundle of muscle fibers that is fed by a single motor nerve.) Some very interesting studies have shown how improvements in muscle performance derive from a simple boost in the amount of muscle tissue the brain is able to recruit during exercise—an improvement that is completely independent of structural changes within the muscles themselves.
For example, in one study subjects engaged in a strength-training program for the calf muscles of only one leg, while leaving the other leg alone. After six weeks, maximum voluntary contraction force was improved in both legs. The improvement in the untrained leg was clearly correlated with increased neuromotor output.
Increasing the number of motor units capable of involvement in the pedal stroke—or muscle activation potential—carries a couple of benefits. First, it enables you to generate more force, increasing your maximum power output. While you will seldom if ever ride at maximum power output during a triathlon, increasing your maximum power output enables you to ride faster at any given percentage of your maximum.
Greater muscle activation potential also enhances endurance due to a phenomenon known as motor unit cycling. During sustained cycling, your brain seldom activates more than 30 percent of the available muscle units simultaneously. However, it constantly changes the specific motor units it activates, allowing some to rest while others take their turn.
By increasing the pool of muscle fibers capable of contributing to the pedaling action, you increase the amount of rest opportunity for each so you can sustain a given speed longer before motor units begin to fatigue.
Practice Makes Perfect
Experienced athletes have much higher muscle-activation potential in their sport-specific movements than inexperienced athletes and non-athletes. Likewise, athletes of any experience level have higher muscle-activation potential when they are in peak shape than when they are relatively out of shape.
A beginning or out-of-shape cyclist may only be able to activate 50 percent of his or her available motor units while riding at maximum power, whereas a world-class track cyclist in peak form will be able to activate closer to 80 percent.
Increasing muscle-activation potential should be a high priority for relatively inexperienced triathletes and for every triathlete in the early stages of training for a peak race (that is, the base phase of training).
To increase muscle-activation potential you must perform very short, near-maximum-intensity efforts, such as 30-second hill sprints. Only when you demand maximum or near-maximum power production from your muscles does your brain begin to activate its least-preferred fast-twitch fibers.
As you begin to increase the number of these intense efforts you complete in a workout from, and then increase their duration and slightly decrease their intensity, you will enhance the endurance-performance characteristics of these strength/speed specialist fibers and make them vital contributors to your race-intensity efforts in the later training phases.
Following is a 12-week schedule of neuromuscular-training workouts that are designed to:
- Increase your muscle-activation potential during cycling
- Increase the endurance characteristics of your newly recruited fast-twitch fibers