By Ian McMahan | Photo by Delly Carr
The sport of triathlon has many great attributes, but being economical generally isn’t considered to be one of them. But aside from shelling out hundreds for race fees and thousands for bikes and carbon wheels, being economical—at least physiologically—can pay big dividends at the end of the race.
In all but the shortest of sprint triathlons, events fall squarely in the aerobic arena. Thus, performance is largely dependent on the three pillars of aerobic endurance: maximal oxygen consumption, lactate threshold and economy. While the first two are generally well known to triathletes, economy and its related term—efficiency—refer to the energy cost of swimming, riding or running at a constant pace. It can be considered the “miles per gallon” measure of endurance sports.
But despite its importance, economy is often overlooked. “Of the three, economy may be the most important. Sport science, however, knows less about it than the other two, so it doesn’t get the same level of publicity,” explains Joe Friel, author of “The Triathlete’s Training Bible” and “Fast after 50.”
“There is no one who has so much talent that they can overcome poor efficiency in races and training.”
“Efficiency and economy of movement become extremely important in long-course racing, which is very popular,” says Jim Vance, head coach of the Formula Endurance triathlon team and coauthor of Triathlon Science. “There is no one who has so much talent that they can overcome poor efficiency in races and training.”
While top-end speed is vital, the ability to exert minimal energy to exercise at a constant pace often dictates performance. Those who expend the least energy can generally go longer and save an extra little kick for the finish.
However, the concept of movement economy is more complex in triathlon than in single-discipline endurance sports. A triathlete has to worry about not only economy in three different sports, but also how effort and energy expended in one discipline relates to performance in the next.
How important is efficiency for improving performance in the water? “Very,” says Dr. Veronica Vleck, who has published extensive research on the physiology of triathlon. “How many times have you seen a highly muscular triathlete powering up and down the pool much slower than a young competitive swimmer with much less muscle and far better technique?”
For swimmers, improving efficiency primarily comes from refining their technique. Sara McLarty, professional triathlete and creator of Swim Like a Pro says, “The most efficient swimmers learn to use the water rather than struggle against it.”
Rather than being dogmatic in her teaching technique, McLarty subscribes to the “middle” approach in terms of the most efficient swimming stroke—with one end of the spectrum being the “kayak,” in which arms move in opposition of each other, and the other style being the “catchup,” where only one arm moves at a time. “The majority of successful swimmers will fall in the middle,” says McLarty.
For triathletes, the strong lungs they develop while swimming can pay off both in the pool and on the road. A 2015 study in the Scandinavian Journal of Medicine & Science in Sports assessed the effects of controlled-frequency-breathing workouts (hypoxic swim training) on lung function in 18 novice swimmers. The swimmers were divided into two groups to complete 12 training sessions. The controlled-frequency-breathing group took two breaths per length, and the stroke-matched (standard) group took seven. The biggest finding was not the expected improvements in several measures of lung function, but the 6 percent improvement in running economy.
The authors of the study concluded that limiting breathing frequency during swimming may enhance running economy through associated changes in lung function. More traditional, stroke-matched breathing did not improve running economy. However, the study notes that these effects may be more marked in athletes with less swimming experience.
Although triathlon-specific cycling economy has not been studied extensively, a great deal of research has addressed economy in cyclists. One such study, published in the 2009 edition of the journal Medicine & Science in Sports & Exercise, examined efficiency in elite cyclists. The researchers concluded that as VO2 max typically peaks within two to three years of starting training/racing, changes in efficiency seemed to explain part of the long-term performance improvement in the trained cyclists.
Similarly, in a study investigating the effects of maximal strength training on the cycling economy of competitive road cyclists, Norwegian researchers found a 5-percent improvement in cycling economy after an eight-week resistance training program (4 sets of 4 RM, 3 × per week). The cyclists in the strength-training group were also able to ride 20 percent longer at maximum aerobic power before they reached exhaustion. Both of these improvements were achieved without a gain in aerobic capacity or body weight, leading researchers to hypothesize that the performance changes were largely related to the nervous system.
What’s more, the longer time to exhaustion suggests that the cyclists’ improved economy delayed the onset of muscular fatigue. Because of the positive changes seen in the study, the researchers recommend, “We advise cyclists at both recreational and higher levels to include maximal strength training as a supplement to their endurance training program.”
Focusing on efficiency during cycling may have an even greater effect in Masters athletes. It’s well established that athletes progressively lose maximal aerobic capacity and muscular strength as they age. With this loss in muscular strength comes an associated loss in efficiency, as a greater proportion of muscle must be used to power each pedal stroke.
With the goal of defining some of the age-related changes in performance, researchers from the French National Institute of Sport and Physical Education specifically investigated the effects of maximal strength training on the efficiency of trained Masters cyclists.
The results, presented in the European Journal of Applied Physiology, should send every Masters triathlete hurrying to the gym: a 14-percent increase in efficiency after just three weeks of maximal strength training (10 × 10 repetitions using 70 percent of maximum aerobic power, 3 × per week). While efficiency also improved in the younger athletes in the study, the results were much more marked in the older athletes, possibly because of the greater strength deficit seen in the group.
Friel also believes in the importance of muscular efficiency, stating, “Strength training is believed to increase the strength of the slow-twitch muscle fibers so that they can create more power before the fast-twitch fibers must be enlisted. Once the fast-twitch fibers kick in, economy declines.”
It may also be important for triathletes to dedicate time to improving their pedaling technique. Research comparing the pedaling techniques of cyclists and triathletes determined that triathletes expend more muscular energy to produce the same amount of work, likely owing to a difference in technique. The conclusion is that this lowered efficiency would likely have a negative effect on later running.
Vance also believes that with the importance of applying force at the highest rate possible for the desired timeframe, cadence as a whole must be addressed, not just in cycling, but in running and swimming as well. “The higher the cadence an athlete can hold, the less force they need to apply with every swim or pedal stroke, or running step, which allows for energy conservation,” Vance states.
While research hasn’t conclusively established an “optimal” cadence, Vleck’s research on the Great Britain Cycling Team has led her to suggest that a higher cadence lessens the chance of injury. “You don’t want to be applying ‘unfortunate’ forces through the knee every single time you turn your pedals,” she says.
Much of the research on economy in triathletes has focused on effort and technique during cycling and how it influences subsequent running. Biomechanically, this transition is demanding, as the change involves impact, a different range of movement and a change from a non-weight-bearing activity to a weight-bearing one. These changes are often most obvious at the start of the run, but they can have lasting implications on performance.
“The higher the cadence an athlete can hold, the less force they need to apply with every swim or pedal stroke, or running step.”
While studies have shown that running performance after cycling is diminished by up to 10 percent as compared to isolated running, optimizing running is critical to success in triathlon. Notably, prior cycling has been shown to impair running economy. While many of the changes in running economy after cycling are due to dehydration and other physiological changes, alterations in running technique are also to blame.
Research in this area suggests that cycling influences running gait and muscle use in some triathletes, resulting in a cycling-related decrease in running economy.
According to a 2010 study in the Journal of Science and Medicine in Sport, changes in the position of the ankle and knee when the foot meets the ground during the running stride were associated with the greatest loss in economy. More pronounced heel-striking and a straighter knee at impact were both associated with a greater loss of energy with prolonged running.
The authors of the study suggest, “Training interventions aimed at restoring running kinematics after cycling may benefit some triathletes’ performance.” In other words, add some bricktype cycling-running technique workouts to your training plan.
Other research has also correlated post-bike running technique changes with exercise-related leg pain. In an article published in the International Journal of Sports Physiology and Performance, researchers investigated the effects of a variable cycling power distribution on running. Twelve well-trained triathletes performed two experimental one-hour cycling trials, both at the same average power, at either variable power or constant power, followed by an outdoor 9.3 km time-trial run. Even though their average power was equal, cyclists who showed a fluctuating cycling power output also ran more slowly.
The authors of the study concluded that cycling with variable power output hurts subsequent running performance more than cycling with a constant power output, which suggests that maintaining a more even effort will make for the best running performance.
Plyometric training has also shown promise in improving muscular control in athletes most affected by cycling-related biomechanical changes. Research published in the journal Physical Therapy in Sport found that adding plyometric training to endurance training corrected deficiencies in the muscle control of triathletes who had lost muscle function because of cycling. While the positive changes did not extend to running economy, they may help prevent injury.
Similar to cycling, isolated running economy has also been extensively studied. A recent review article in the journal Sports Medicine gives runners (and triathletes) several strategies for improving running economy, a factor the article acknowledges was largely ignored by the scientific community until the last 10 years.
The first method? Run a lot.
As with most activities, practice makes perfect, and several studies have shown improvements in economy after several years of consistent running. Thankfully, the article also suggests improvements in economy that won’t take years or require going through several pairs of running shoes. These more immediate changes can come from heavy resistance training, plyometric training and explosive resistance training.
However, though each of these methods of training improves running economy in all levels of runners, traditional resistance training—particularly using heavy resistance—has resulted in the greatest improvements in running economy. The benefit in economy, usually on the order of 5–7 percent, seems to occur through an increase in nerve and muscle coordination, and changes in the size and strength of both fast- and slowtwitch muscles.
Greater strength means that leg muscles are able to create the same force with less muscular effort, thereby conserving energy and delaying fatigue. Importantly, these improvements in strength are usually realized without an associated gain in muscle mass or body weight.
The bottom line is that improving efficiency will improve performance. As individual and race-specific conditions vary, the controlled nature of research studies means that they don’t always end up providing specific advice for athletes. However, valuable generalizations can be gained from research on efficiency. Primarily, it’s clear that an investment in technique and the addition of a resistance-training program can provide a great deal of improvement in efficiency across all disciplines. And who knows, maybe being extra economical means you can go splurge on some new gear.
This first appeared in the August 2015 issue of LAVA. Get your issue here.
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