Cycling
Several studies support the use of cycling as a cross-training activity for runners. In an investigation carried out at California State University at Northridge, 16 lean, fairly fit runners were divided into two equal groups. For 9 weeks, 8 of the runners engaged only in running workouts, while a second group of 8 worked out only on exercise cycles.1 Each group trained four times per week for 40 to 45 minutes per session, and exercise intensities were equivalent between groups. Two days a week, the athletes simply trained continuously at between 80 and 85 percent of maximal heart rate. On the other two days, the exercisers conducted interval training, with heart rates rising to 90 to 95 percent of maximum during 1- to 2-minute work intervals.
During a typical interval session, six 2-minute and four 1-minute intervals were completed, with 1-minute recoveries after each work interval. The rest of the interval workout consisted of steady exercise at 80 to 85 percent of maximal heart rate, with the entire session lasting for at least 40 minutes.
Before and after the 9 weeks of training, all athletes were measured for both O2max and ventilatory threshold (VT), both while running and while cycling. VT is very similar to lactate threshold, the exercise intensity above which lactate begins to accumulate in the blood. Scientific studies have confirmed that VT can be a reasonably strong predictor of endurance performance.
The runners who engaged in just the cycling training improved markers of running fitness rather dramatically. Even though these individuals had not run a single step during the 9-week period, they increased their running O2max by 15 percent and running VT by 13 percent; in addition, they increased their cycling O2max by 15 percent and cycling VT by 31 percent. The athletes also increased their running O2max from 55 to 63 ml • kg-1 • min-1 and their cycling O2max from 50.5 to 58 ml • kg-1 • min-1. For an athlete who both runs and cycles, running O2max is often higher than cycling O2max, presumably because in running the oxygen-using muscles are required not only to push the body forward but also to support body weight, while in cycling the bike holds the athlete upright; the additional work required for running pushes oxygen-consumption rate upward.
Surprisingly, the runners who carried out only running training did not improve running fitness to a greater extent than the bike-using trainees. These runners increased running O2max by 18 percent and running VT by 17 percent, about the same gains achieved by the cyclists.
This investigation indicates that cycling can promote large gains in aerobic fitness in fairly experienced runners. Even when cycling training is carried out by itself, without complementary running training, it can produce major gains in running aerobic capacity over a 9-week period. However, this would probably not be the case in highly trained elite runners who have already come close to maximizing their running aerobic capacity. This does not mean that elite runners should avoid high-quality biking, however; for such athletes, powerful bike sessions might produce other advantages, including upgraded leg strength and superior blood lactate removal.
Implications for Triathletes’ Training
Triathletes may be particularly interested in the study reviewed in the previous section since the results revealed that 9 weeks of running training boosted cycling O2max by only 9 percent and failed to lift cycling VT at all. Since 9 weeks of cycling increased cycling O2max and VT and running O2max and VT to a considerably greater degree, it seems evident that the cycling workouts in a triathlete’s program may have a broader impact on overall fitness than running sessions. If cycling and running capacity have been equally advanced by prior training, a triathlete might reasonably select cycling over running on an open training day when the greatest overall advance in fitness is desired.
Gaining Fitness With Less Risk of Injury
In a separate study carried out at the University of Toledo, 10 well-trained runners who were averaging 30 to 35 miles (48-61 km) of running per week added three weekly bicycle workouts to their existing schedules over a 6-week training period.2 The supplemental cycling sessions were quite simple: On Mondays, the runners carried out five 5-minute work intervals on exercise cycles with heart rates at 95 to 100 percent of maximum during the intervals, which were always followed by 5-minute recoveries. On Wednesdays, the runners pedaled continuously for 50 minutes, with heart rates at around 80 percent of maximum. Each Friday, the runners added three 150-second cycling intervals and six 75-second cycling intervals at close to maximal intensity with rest intervals equal in duration to the work intervals.
The added cycling training did not have any adverse effects on the runners’ endocrine, immune, or muscular systems; there was little sign of overtraining. Most important, the supplemental cycling produced physiological and performance bonuses. After six weeks, perceived effort during highly intense running was lower: The runners felt that difficult running speeds were easier to sustain. In addition, the runners’ 5K times improved by almost 30 seconds, from 18:16 to 17:48. This study suggests that the addition of cycling training to a running program can produce gains in fitness and competitive performance.
The gains achieved by the runners who added cycling to their training were the same as those attained by another group of runners who added a trio of running workouts to their weekly schedules. In other words, from the standpoints of physiological and competitive improvements, adding extra running to the programs of experienced runners was not more effective than adding cycling sessions. Over the long run, the addition of cycling might be more effective than extra running since the cycling would be less likely to produce damage from eccentric strains or from impact with the ground in the tendons and muscles of the legs during training; thus, postworkout recovery would be quicker.3
An inescapable conclusion from the Toledo research is that many runners would probably be able to improve their performances and decrease perceived effort during intense running by adding cycling workouts to their training programs. Cycling seems to allow runners to add more high-quality work to their schedules without heightening the risk of leg-muscle strain. Many runners who ordinarily can handle just two quality workouts per week can step up to three high-intensity weekly efforts, provided the third exertion is on the bike rather than on the feet. There is also evidence that runners can complete supplemental bike sessions at higher intensities (i.e., higher percentages of O2max) compared with supplemental running workouts.3
Runners including cross-training for the first time in their overall programs can do well by adding one cycling workout per week to their existing schedules. The number of weekly cycling sessions can gradually increase to two, one hot and one cool. The hot cycling session can incorporate high-intensity intervals ranging in duration from 30 seconds to 5 minutes, along with hill climbing and even difficult tempo rides lasting for an hour or so. Cool cycling would consist of 45 to 60 minutes of easy pedaling; this permits more recovery on a day following a hard running workout compared with running for the same amount of time.
Improving 10K Times With a Stand-Up Routine
It’s no joke; there is also evidence that cycling training can improve 10K running performance. In a study carried out with year-round runners between the ages of 18 and 65 who had been competing for at least 3 years, nine individuals (five males and four females) supplemented their running workouts with interval training on exercise bikes.4 The key investigator in this study, Tom Miller, had been influenced by statements made by Olympic gold medalist Frank Shorter and six-time Ironman champion Dave Scott that standing up on bicycles while pedaling intensely uphill had positively influenced their running performances, and thus Miller required his bike-interval trainees to conduct their bike intervals standing on the pedals as they rode. Work-interval cadence was set at 75 to 90 revolutions per minute, and pedal resistance was heavy, so that the overall effort was comparable with running up a steep hill at maximal possible speed.
Toe clips were removed from the bikes to ensure that the runners’ main muscular work was an active pushing down on the pedals. The interval session
s, conducted once a week over a 6-week period, always began or ended with 10 minutes of warm-up or cool-down.
All bike workouts used a pyramid work-interval scheme with this sequence of work intervals: two at 30 seconds each, two at 45 seconds, two at 60 seconds, two at 45 seconds, and two at 30 seconds. Each 30-second work interval was followed by 15 seconds of spinning (i.e., pedaling at 90 rpm against light resistance), while 45- and 60-second intervals were followed by 30 seconds of spinning. The spin segments were designed to simulate downhill running after an intense uphill climb. Sixty seconds of recovery while pedaling at only 60 rpm against comfortable resistance followed each work-spin combination. Overall, spin pedal resistance was about one-half of work-interval resistance, and recovery resistance was approximately one-third as great.
Each biking interval workout proceeded as follows: 10 minutes of warm-up, a 30-second work interval, 15 seconds of spinning, 60 seconds of recovery, another 30-second work interval, 15 seconds of spinning, a 60-second recovery, a 45-second work interval, 30 seconds of spinning, 60 seconds of recovery, and so on. Pedal resistance was increased whenever the athletes found it fairly easy to complete their work intervals and was lessened if pedaling rate dropped below 75 rpm during work efforts. The runners were always encouraged to replicate their running motion as much as possible during work intervals. Spins and recoveries were completed while seated.
After 6 weeks of the supplemental biking interval training, six of the nine subjects achieved personal best 10K times, and average 10K time for the group improved significantly by 8.6 percent from 47:09 to 43:07. All the athletes reported that after the bike training, they felt stronger while running on hills and also during the closing mile of the 10K than they had at the beginning of the research.
Preserving Running Fitness During Off Times
Science suggests that cycling can preserve running fitness during a complete furlough from running, which might occur following a running injury, even when all of the cycling training is moderate in intensity.5 In a study carried out at the University of Waterloo in Ontario with 12 female runners, one group of 6 runners continued their usual running training program, running about 30 minutes per day, 4 days per week, at an intensity of 80 to 85 percent of maximal heart rate (i.e., a level of effort corresponding with about 70-76 percent of O2max). A second group of 6 runners did not run at all during the 4-week period but instead used exercise bicycles to train with a similar frequency and intensity: 4 days per week, 70 to 76 percent of O2max. Individuals in the two groups were identical in training background, height, weight, and percent of body fat.
Running capability was assessed by asking the participants to warm up and then run as long as possible on a treadmill at an intensity of 90 percent of O2max, or about 95 percent of maximal heart rate. Prior to the 4-week study, the runners who participated only in cycling during the research could run for an average of 16 minutes during this key test. After the 4 weeks of cycling with no running, these individuals could still run for 16 minutes at 90 percent of O2max, indicating that there was no drop-off in performance. Running O2max was also maintained during the 4 weeks of cycling, resting steady at about 50 ml • kg-1 • min-1. O2max can ordinarily decline by as much as 7 percent in as little as 3 weeks when little relevant training is performed. It is clear that biking constitutes appropriate training from the standpoint of preserving running fitness.
Stair Climbing
Science indicates that the use of a stair-climbing machine can also have a beneficial impact on running O2max and performance.6 In another study carried out at California State University at Northridge, 11 active college women carried out solely stair-climbing workouts for 9 weeks using an automated stair machine that is quite similar to a downward moving escalator, while 12 other women participated solely in running workouts on an outdoor track. Each group worked at the same intensity—70 to 80 percent of maximal heart rate—for 30 minutes per workout, 4 days per week, over the first 2 weeks of the study. During weeks 3 through 9, all athletes trained at 85 to 90 percent of maximal heart rate, 4 days per week, for about 40 minutes per workout. Before and after the 9-week training period, all the women ran a 1.5 mile (2.4 km) race and had their aerobic capacities measured.
At the end of the 9-week period, it was virtually impossible to distinguish the stair-machine users from the runners during running, even though the stair-machine users had carried out no pure running training at all. Race times improved by 1 minute for the stair-machine users and by 1.4 minutes for the runners, but the difference was not statistically significant. O2max—measured while running—rocketed upward by 12 percent for the stair climbers and by 16 percent for the runners, a difference that was not significant. Each group improved by a similar amount during submaximal running. Prior to the 9 weeks of training, the chosen submaximal tempo had forced the women’s heart rates to reach 90 percent of maximum; following the stair climbing and running training, heart rate for both groups had settled at a calmer 84 percent of maximum at the chosen pace.
Although running performances were similar between the groups, the stair climbers did enjoy an advantage over the runners: They didn’t get injured. Two runners had to drop out of the research due to serious injuries, and two other runners missed valuable training time because they were hurt. Due to its low-impact characteristics, stair climbing appears to carry a significantly lower risk of overuse injury compared with running.
After 9 weeks, when running at a very moderate intensity of 66 to 72 percent of O2max, the running group relied less on carbohydrates and more on fat to fuel their efforts; the stair-climbing group relied more heavily on carbohydrates. The mechanism underlying this finding may be that the muscular power required to lift one’s body against gravity during stair climbing may increase the recruitment of fast-twitch muscle fibers, which are notoriously weak at fat burning. It will be interesting to see whether stair climbing has positive effects on hill-running ability and sprint speed (to date, no research has been conducted in these areas).
This study suggests that stair climbing has a positive effect on running performance and running aerobic capacity. Note, however, that the women in the study were relatively untrained at the beginning of the research; the positive effects associated with stair climbing might have been the result of training rather than the outcome of a unique transfer of fitness from stair climbing to running. It should be noted also that unlike the situation with cycling, no research has examined whether the addition of stair-climbing workouts to an experienced runner’s training regime can heighten running performance.
Nonetheless, it is quite likely that stair climbing can be beneficial for runners: When climbing stairs, the work output per step is significantly greater compared with flat-ground walking, an effect that should strengthen the muscles. Also, stair climbing without holding onto the bars of the stair machine should advance coordination and stability during gait. Finally, there is little doubt that high rates of oxygen consumption and lactate production can be attained during stair-machine exertion, effects that could easily spur gains in O2max and lactate-threshold velocity.
Aqua Running
Although its popularity appears to be decreasing in recent years, aqua running has been an attractive cross-training activity to runners for a number of reasons:
Mimics running form. Normal running form can be almost completely replicated during aqua-running movements even though there is no impact with the ground and no stance phase of gait, so there is a reasonable hope that running-specific neuromuscular patterns will be preserved and running-specific strength will be maintained, perhaps to a greater extent than would be the case with cycling.
Aids in recovery. Unlike regular running, aqua running features has no impact with the ground. Thus, recovery from intense or prolonged aqua-running sessions is probably quicker than from running on firm surfaces because there is less strain on muscles and connective tissues.
Promotes flexibility. Compared with normal ground running, greater
range of motion is often attained in the water, perhaps promoting flexibility and dynamic mobility, two areas of weakness for many runners.
Offers high-intensity exercise. High levels of exercise intensity are possible during aqua running; high heart rates, rates of oxygen consumption, and lactate levels can be achieved readily along with possible corresponding gains in O2max and lactate-threshold velocity.
Aqua running can be a valuable way to maintain fitness when an injury makes running on firm ground impractical or painful.
Lucenet Patrice/Phototeque Oredia/age fotostock
Scientific research has generally supported the idea that aqua running can have a positive impact on running fitness and performance. In a study carried out at Brigham Young University in Provo, Utah, 32 runners who could complete a 1.5-mile (2.4 km) run in less than 10:45 (i.e., at faster than 7:10 pace) were divided into three groups with equal levels of fitness: (1) 10 trained exclusively by running in deep water while wearing life jackets; (2) 11 trained only on exercise bicycles; and (3) the remaining 11 continued their usual running training. All 32 athletes trained five times a week, 30 minutes per day, at an intensity of approximately 80 percent of maximal heart rate.7
After 6 weeks of such training, O2max (measured while running on a treadmill) remained equivalent between the three groups, even though the cyclists and aqua runners had not carried out a single running workout. Somewhat surprisingly, all three groups improved 2-mile (3.2 km) race times by 1 percent perhaps because the subjects were training a little more than they usually did. This study suggests that aqua running can preserve aerobic capacity and upgrade performance in medium-level runners even when it is carried out to the exclusion of firm-ground running workouts. However, the training load used in this study—five 30-minute workouts per week—might have been greater than the load preceding the study, and thus the upgrade in 2-mile (3.2 k) race performance could have been the result of an increase in the amount of training rather than a specific aqua running effect. Even if that were the case, the gain in competitive fitness was as large for aqua running as it was for regular running.
Running Science Page 25