A video posted to Chris Froome’s Twitter account in July 2019 shows him sat atop his Pinarello, pedaling away on a stationary trainer. Just six weeks after his horrific crash while pre-riding Stage 4 of this year’s Critérium du Dauphiné, the Kenyan-born Englishman was back on the bike. But not all of him; only his left leg. Froome’s right leg, the one whose femur was shattered by a concrete wall, was still straight, still healing, and not yet ready to be pushing on the pedals.
But that didn’t stop Froome. He insists his career is not over, despite critics and medical experts saying that it is impossible for a 34 year-old to return to elite sport after such a gruesome injury. Yet he keeps on pedaling, determined to return to racing, and even make a run at the Tour de France…
While the single-leg (SL) pedaling may be standard recovery protocol, there may be more to it than meets the eye. Studies have shown that SL pedaling can lead not only to minor fitness gains, but also to improved neuromuscular activation patterns, overall leg strength, and cycling efficiency. This is food for thought, and after reading through all of the details, you may want to start incorporating SL pedaling into your own training plan.
What is SL Training?
Single-leg training is when you pedal with only one leg. It’s that simple. Best done on an indoor trainer, these intervals are designed to improve your pedaling efficiency by forcing you to exert power through the entire pedal stroke, not just on the push or pull.
Benefits of SL Training
A 2011 study published in the Journal of Applied Physiology showed that experienced cyclists could, after just a two weeks of performing SL workouts, generate the same power with less perceived exertion and leg pain (Triathlete). Studies have also shown SL pedaling can be used to maintain cardiovascular fitness following injury to one limb. One article from the Journal of Orthopedic and Sports Physical Therapy took individuals through a 7-week training program which included four days per week of high-intensity SL pedaling: 15-20 intervals lasting 20 seconds in duration during each session (Bell et al. 1988). Participants saw a significant increase in their VO2 Max following the 7-week protocol, an average of 9.8% in their trained leg; and more incredibly, VO2 max also increased by an average of 6.5% in the untrained leg.
SL pedaling may actually be better than double-leg pedaling, in some cases. A 2011 study in the Journal of Applied Physiology showed that participants who engaged in bouts of high-intensity SL pedaling intervals saw “greater enhancement in the metabolic and oxidative potential of skeletal muscle” compared to their double-legged pedaling counterparts (Abbiss et al. 2011). (For the super nerds out there: it was the Thr-phosphorylated 5′-AMP-activated protein kinase α-subunit and cytochrome c oxidase subunits II and IV and GLUT-4 protein concentration that researchers looked at specifically).
Another benefit of SL drills is their ability to identify imbalances and leg strength discrepancies. Dual-sided power meters can do this for us, but most riders don’t have that luxury. By practicing 1-minute on/1-minute off SL drills, riders can identify leg strength discrepancies as soon as they hit the 45-second mark. If your right leg feels dead after 45 seconds, but your left feels strong, it is the right leg that needs your attention. Discrepancies can be addressed through strength training, physical therapy, flexibility work, and of course, more SL pedaling. Evening out the discrepancy early on will help prevent more serious, chronic injuries from developing down the road.
On a broader spectrum, SL pedaling has been shown to be an effective exercise regimen for ventilatory-limited patients, specifically those with Chronic Obstructive Pulmonary Disease (COPD) (Dolmage and Goldstein, 2006). The authors of this study showed that by targeting a smaller muscle mass through SL pedaling, as opposed to two-legged pedaling, patients were able to increase both the duration and total workload of their exercise bouts. Findings like this suggest new, innovative ways of enhancing the exercise function of physically-limited patients.
Contralateral Effects
Did you know that you can increase your left leg strength by only exercising your right leg? This is contralateral strength, defined as the increase in muscular strength seen in homologous muscles, of which only one side was trained. This is believed to be a “spillover effect” from the neuromuscular system and increased motor neuron output. Countless studies have shown muscular strength increases of 10-40% in the contralateral (untrained) limb (Carroll et al. 2006).
Seems like Mr. Froome might be onto something…
With SL pedaling drills, a rider can not only improve their overall efficiency, leg strength, and pedal stroke smoothness, but also rehab from injury even when one side is compromised. By pedaling with his left leg only, studies have shown the Froome’s right leg strength could increase significantly, up to 40%, especially when you consider the alternative: bed rest and severe muscle atrophy.
Risks of SL Training
SL intervals are not meant for group rides, outdoor riding, or HIIT sessions. They are best completed on a stationary trainer at an easy to moderate endurance pace. This allows the rider to keep full control of their bike, and focus on the pedal stroke and technique rather than where they are going/what they are about to run into. SL pedaling at a lower power output allows you to focus on the technique rather than the effort. Once you’ve mastered the smoothness of the pedal stroke, you can start increasing the workload as a way to boost muscle strength and generate more power throughout the whole of the pedal stroke.
How to Incorporate SL Pedaling Into Your Training
When performing SL drills, make sure you stabilize your non-pedaling leg on something such as a box or the frame of the trainer. You want to keep your weight distributed evenly over the saddle, as you would when pedaling normally. Focus on your form and technique. Maintain pressure all the way through the pedal stroke: up, down, and all around.
DON’T: jam on the down stroke and coast back up to the top; point your toes toward the floor; use your whole body (head, arms, and torso) to push and pull your leg around the pedal stroke; overthink it. SL pedaling should feel natural after just a little bit of practice.
DO: push evenly on the down stroke, when the crank arm moves from the 12 o’clock to the 6 o’clock position. Keep your heel down through the bottom of the pedal stroke, and pull the pedal up and over the top of the stroke – This is usually the hardest part, from the 11 o’clock to the 2 o’clock position. Squeeze your core and keep the pressure on the pedals up and over the top.
Start with 30 seconds on each leg, with 30 seconds of rest (double-legged pedaling) in between. Then, progress to 45, 60, 90, and 120 seconds. When that gets too easy, try some high-intensity SL intervals. Again, go back to 30 seconds with one leg, 30 seconds off, 30 seconds with the other leg, and so on. And if gets too easy? Go outside and try dropping your riding buddies with one leg.
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Sources
Froome tweet: https://twitter.com/chrisfroome/status/1153983012515848194?lang=en
Master an Efficient Pedal Stroke with Single-Leg Drills (Triathlete): https://www.triathlete.com/2017/02/bike/master-efficient-pedal-stroke-single-leg-drills_298462
Contralateral effects of unilateral strength training: evidence and possible mechanisms (Carroll et al. 2006): https://physiology.org/doi/full/10.1152/japplphysiol.00531.2006
Response to one-legged cycling in patients with COPD (Dolmage and Goldstein, 2006): https://www.ncbi.nlm.nih.gov/pubmed/16478848
The influence of one-legged training on cardiorespiratory fitness (Bell et al. 1988): https://www.ncbi.nlm.nih.gov/pubmed/18796979
Single-leg cycle training is superior to double-leg cycling in improving the oxidative potential and metabolic profile of trained skeletal muscle (Abbiss et al. 2011): https://www.physiology.org/doi/full/10.1152/japplphysiol.01247.2010