The Key Differences: Road vs Zwift Riding

Riding on Zwift indoors vs riding out on the road/trails is NOT the same.  There is a plethora of evidence to support this.  

I have been a long time supporter of using both as very powerful tools in order to build strength and fitness relative to your cycling goals. However, there are TWO key differences in riding on the road vs indoors that you must take into consideration when planning your bike-specific strength work: wind resistance and the movement of the bike in 2D.

WIND RESISTANCE:

Whether your hands are on the bars, your butt on the saddle, or your feet on the pedals, you always have some sort of feedback coming from the bike. And this feedback allows you to adjust your position and change the way you're activating your driving and postural muscles while on the bike.

Feedback also comes in the form of wind resistance.  This wind resistance ultimately works to 'hold you up' on the bike - in a good way.  Let me explain.

There is a term called 'visco-elastic creep (VEC)' in the musculoskeletal system.  And what that means is that over time spent on the bike, your muscles, tendons and ligaments (and more) progressively lengthen and deform over time. On the bike it means we're flexing our spine more (DON'T read into this being a good thing about getting more aero (which isn't a high priority on Zwift) as there are strategies in place to get aero, and this ISN'T one of them). To learn more on this, watch a mini lecture by Dr Kevin Kirby HERE.

This is something we want to avoid, because it can affect the length tension relationship of the muscle (ie: the longer the muscle 'creeps' the less likely it is to do the desired job) and/or it can place more point loading on tissues (think point loading in the lower back with increased spinal bend) which can increase the likelihood of injury.

When on the road, the feedback re get from wind resistance, which is something that we are trying to minimise the effects of - ie: become more aero, is also something that we can use to our advantage: it allows to hold our desired position longer reducing the effect of VEC.

Therefore, it is common to see riders who spend more time training on Zwift etc having more postural issues particularly around the lower back and neck/shoulders.  This module is going to outline plans and solutions to reduce this risk, to enable you to get more out of your Zwift sessions. 

FIXED BIKE POSITION VS 2D MOVEMENT:

Sure, there are some smart trainers coming out that are starting to replicate the 'normal' movement of the bike when ridden outdoors, but they are +++ expensive and therefore only in the hands of the wealthier few. For the sake of thise section, I am going to assume you're on a fairly standard 'fixed' indoor trainer.

As a Biomechanist that has dedicated years of his life to providing the most effective solutions for the athlete to increase their inefficiencies, on the bike my No. 1 pet peeve when watching the inefficient rider is when they are out of the saddle.  

Think of the bike as an aid to moving forward faster when out of the saddle.  When you watch the top riders in the world, they sway their bikes side to side considerably. WHY? Because by using the triceps and biceps to sway the bike, these fairly small muscles are creating a HUGE positive effect: they're bringing the pedal up to meet the foot, thereby reducing the work in the legs to generate the same forward movement.

Watch this video HERE of Wout van Aert winning Kuurne-Brussels-Kuurne from the front on view.  The sway of the bike is significant.  Let's break it down:

1. His trunk is ultimately dead still, with the bike moving underneath him
2. As the bike leans to the left (using biceps and triceps (arm muscles)), thereby bringing the right pedal vertically up, the right foot stomps down.
3. Therefore, it's almost free energy as the small arm muscles are working to take the pressure off the leg muscles.

On a fixed indoor trainer, this doesn't happen.  Is this a bad thing? Ultimately NO, but if you're wanting to get optimal cross-over from Zwift to the road, then it's worth taking this into consideration when working on your road out-of-saddle technique.

There are other areas where there are evidence-based differences (cadence, climbing technique0, so keep this in mind and exploit Zwift for what it is: an amazing tool for dialling in your efficiency and economy in a highly repeatable environment.