Improve Your Pedalling Efficiency Part 2: Exercise and Bike Fit Solutions to Imbalances
Analysing top dead centre and the first quarter of your pedal stroke can indicate solutions to improve technique.
May 14th 2020, By Richard Rollinson
Following on from Part 1 of Improving Your Pedalling Efficiency, where we covered what to improve on to increase the economy of your pedal stoke. In part 2, you will discover how to work on identified key areas to improve on.
Strength Exercises to correct
Let’s look at what pedalling imbalance issues can potentially be worked on with the aim of improving Strength is specific muscle groups:
- Power phase start and finish angle differences between left and right.
- Power phase length angle differences between left and right.
- Angle of your foot through the entire pedal stroke.
- Angle of your foot through the top quarter of the pedal stroke.
- Pelvic and Torso rock.
Solutions can be found to fix imbalance and technique issues with analysis of your pedalling and motion metrics.
A difference in power phase start angle between left and right is often reflected in a difference in the angle of your foot in the first quarter of the pedal stroke from top dead centre, with the heel dipped and toe up that may be predominant on one side more than the other. This can indicate a weaker calf on the leg with heel down.
This can mean that the opposing muscle groups can be significantly stronger, which would be the opposing calf and upper leg muscles on the same leg and potentially weaker upper leg muscles on the opposing side.
To work on this within your regular strength training workouts;
- Perform 1 set of calf raises with your planned or usual repetitions, only on the identified weaker side and 1 set with both legs.
- Perform 1 set of squats and lunges with the opposite leg to the one worked on more with the calf raises.
Pelvic and torso rock can be a result of a weaker core that is not able to make the most of the strength in your legs. By increasing core strength through a variety of weights and bodyweight exercises, this can reduce pelvic and torso rock as your extra core strength builds a more solid foundation to keep your upper body and hips more still to make more use of the power available in your legs.
Relationship to Bike Fitting
While we have now covered some pedalling imbalance issues that can be fixed through exercises and technique, there are some that can be improved through bike fit and have a knock on effect to enable you to carry out those pedalling techniques and skills easier.
Let’s look at what pedalling imbalance issues can potentially be worked on through bike fit:
- Pelvic rock and rotation.
- Torso angle and rotation.
- Gross power released and absorbed (GPR and GPA), significant difference between left and right.
- The angular range of your upper leg.
- Platform Centre Offset (PCO), significantly different, left to right, or not far enough into the centre of the pedal.
Gross power released (power produced being used to move your bike forward) and absorbed (non useful power) is one of the most relevant metrics to track your pedalling efficiency.
Excessive pelvic rock can be a sign of too high saddle height, as you have to stretch more to reach bottom dead centre of your pedal stroke, this reaching leads to a tilt down in the pelvis and a tilt up on the opposite side. This often has a knock on effect to having less control at the bottom of your pedal stroke; lower GPR and higher GPA. This can be fixed by lowering to a more optimal saddle height. Pelvic rotation can be opened out or close with shorter or longer crank length. Both of these adjustments can also impact your leg angle.
PCO can be pushed away from your bottom bracket through Q factor pedal axle spacers, if your score is in minus figures and more power is produced closer in towards your bike frame. Cleat shims can also impact PCO by pitching your foot higher and further in towards your bottom bracket.
Where you produce the most torque on your pedals and where you put most power in through your pedal stroke can be measured through most dual sided pedal power meters.
Imbalances that impact on pedalling technique and efficiency can be improved at the foundation first by building a solid core and also fixed through leg muscle imbalances. Realigning your bike to your body also helps in the ease of improving pedalling technique.
