by Alan Couzens, MS (Sports Science)

Part I
Part II - Strength
Part III - Work Capacity

In this final article in the Basic Limiters series I want to talk about the most overlooked of the three: mobility.

Mobility is kind of a catch-all phrase that incorporates all aspects of functional flexibility -- the factors that may restrict an athlete’s range of motion in their chosen sport and general functional tasks. As such it incorporates:

• Muscular tightness
• Soft tissue restriction
• Joint capsule restriction
• And neuromuscular restriction/faulty movement patterns

It is a very important quality to the endurance athlete for two big reasons:

1. Injury prevention
2. Economy

Injury Prevention
Endurance sports are, more or less, whole body activities. On the positive, this fact enables the athlete to put sufficient demand on the body that they get a true systemic training response. All of the systems of the body from circulatory to metabolic to endocrine get a “workout” and, providing appropriate loading and recovery patterns are adhered to, the general health of these systems is enhanced.

The downsides of whole body activities are that:

• The movements are generally more complex
• The opportunity for faulty compensation is rife

Take running for example, say Joe Middleage arises from his slumber on January 1 one year resolved to begin running for fitness. He takes his first few loping strides and his body realizes (unconsciously) that he no longer has the ankle flexibility to drop his heel to the ground at the completion of each stride.

“No problem,” says the body, “I’ll just turn Joe’s feet out a little so the lever length of the foot is effectively decreased and he can manage the movement.”

Of course to do this, Joe is now pronating significantly more at the ankle, his knee is now doing a weird sideways kick instead of hinging backward and forward and because his hip is perpetually externally rotated, he’s swinging his leg back not from the hip but from the lumbar spine. To make matters worse, the faulty movement patterns that Joe is ingraining in these first steps back are becoming ingrained to an extra-strong degree and even if Joe finds the muscular flexibility later down the road, these newly formed motor patterns will be hard to break. In short, Joe is in trouble!

This situation is certainly not limited to the ankle joint in runners. Given the number of movement patterns involved in triathlon. Most joints are used and consequently, a deficiency in mobility in any one of these joints can lead to injury problems. Other common examples:

• Scapulo-Thoracic immobility leads to shoulder issues in the swim
• Hip extensor immobility (relative to position) leads to back issues on the bike
• Hip flexor immobility leads to Achilles and adductor issues on the run

Paraphrasing Mike Clark from his great book “Advances in Functional Training” -- when a joint is immobile in a complex movement, a joint above or below is forced to take up the slack and this mechanism leads to muscles being overworked or working in purposes that they’re not really suited for.

There is nothing more frustrating to both athlete and coach to be unable to access the fitness that you’ve worked so hard for on a given date because of a lingering injury. This is an all too common true limiter in the world of endurance sports.

The obvious solution to Joe’s (and an unacceptably large portion of endurance athletes’) dilemma is to correct flexibility discrepancies in his chosen movement before piling on the miles in said movement!

Economy
If you’re a young, generally healthy, performance obsessed athlete, I may not have sold you on the importance of supplementary mobility work with the above example but perhaps this will…

Several studies on effective running biomechanics have found a distinct interplay between mobility, stability and running economy. For example, Godges et al (1989) found a significant improvement in running economy at all paces with improved hip flexion and extension. In contrast, the same author found improvement in economy with decreased mobility -- improved stability of the hip and trunk rotators. In other words, we want some joints to be very mobile and others very stable and capable of holding lots of elastic energy! Indeed, other researchers have come to a similar conclusion that there is a distinct and consistent pattern to joint mobility/stability in extremely economical distance runners (such as Craib et al., 1996, Gleim et al., 1990, Kyrolainen et al, 2001). In general, muscles of the frontal and transverse plane are relatively tight -- “springy” may be a better term -- while muscles of the sagittal plane are mobile & capable of force production over a long range.

This is not only true in running, but also in swimming, where mobility may be even more important to economy. For example, Jagomagi and Juramiae (2005) found that flexibility parameters alone explained 28% of the performance variance in breaststroke swimmers. Similarly, Silva et al. (2007) found that two of the most predictive variables to 200 IM performance were ankle and trunk flexibility (r=0.73 & 0.55 resp). To put this in perspective, swimming fitness (measured as speed at 4mmol/L of lactate) was less well correlated to 200 IM performance than ankle flexibility!

Now, while it may be true that these complex relationships of mobile and stable joints occur somewhat naturally when a young “blank slate” begins training, in my experience an older more “well written” slate will need to correct a number of dysfunctional patterns that have crept in through a lack of, or an imbalance of, functional movements (for instance, sitting at a desk for eight or more hours per day). The general preparation period of training is the time to do so.

Practical Applications
In general, the economical- and injury-resistant triathlete will want to establish:

• Ankle stability, especially in the frontal plane (via single leg exercise, including barefoot/minimally supported)
• Sufficient ankle mobility in the sagittal plane (via calf raises, inchworms etc.)
• Hip stability in the frontal plane (via single leg exercise with level hips progressing to single leg squats and deadlifts progressing to single leg work on an unstable surface)
• Hip mobility in the sagittal plane (high step ups, cook bridges, lunges with an emphasis on lumbar stability)
• Lumbar stability (CORE!!! Planks, standing presses, pulls, etc.)
• Thoracic mobility (foam rolling, mini crunches, thoracic extensions over stability ball or off bench, overhead squats, wall angels)
• Scapula mobility (Pectoralis and rhomboid self myofascial release, scapula depressions from a pull and push overhead and dip variety, scapula retractions/full rows)
• Shoulder stability (Swiss ball push up -- hands on ball, single arm work -- push up/plank variations, dumbbells, etc.)

Incorporating the above into your general strength/mobility circuits in the general prep phase of training will go a long way towards attaining some of the movement economy benefits discussed, and perhaps more importantly it will significantly mitigate the chance of a chronic injury limiting the expression of the fitness that you’re worked so hard for in 2012.

Train smart