Part 1 was Jeff Cubos, Chiropractor and Performance Therapist
Part 2 was John Godina, World Athletics Center founder & Elite Shot Putter
Part 3 was Questions & Answers from Peter Weyand’s Research
Dr. Thomas Lam is the President, Director of Sports Science at www.fitstoronto.com
Dr. Lam graduated from the University of Toronto in 1998 with a Bachelors’ of Physical and Health Education, and then went onto study at the Canadian Memorial Chiropractic College, graduating in 2003. Since he has been in private practice and in 2007 he started FITS a high performance training centre and sports medicine clinic that features a movement based approach to prevent injuries, manage existing injuries and enhance performance. FITS is a dream come true for Dr. Lam, whose passion is to build a world leading company that Builds Better Athletes and the health of a nation
Friday Five is sponsored by Freelap Track and Field, a leader in electronic timing.
Interview with Dr. Thomas Lam, Movement Based Sports Science
Q1) Screening is evolving and you screen athletes all the time with a battery of tests. Last year at the BSMPG conference power and technique with jumping was gaining momentum as a functional evaluation for athletes. Could you briefly look at what you look for in bilateral and single leg jumping with the Optojump, specifically with stiffness? (Could we change this to force plate, because we do much more with our Force Plates)
Dr. Lam: By utilizing force plate data we gain valuable insights into the symmetry of the athlete and the reactive abilities of the athlete between sides and across a battery of tests. Reactive abilities look at how the athletes utilize momentum which involves the stretch shortening cycle and the complex coupling of storage and release of energy. A great example is a drop hop, which involves stepping off a low box (12”) and immediately hop upon landing on one leg. The ground contact time and how high the athlete jumps is used to calculate their Reactive Strength Index or it provides us with an indication of their reactive abilities (RSI = height jumped (m) / ground contact time(s).
Now these two kinematic metrics (ground contact time, and jump height) are combined with other kinematic metrics such as joint range of motion (at the knee, hip, and ankle), joint velocity, and an overall assessment of movement, with kinetic metrics such as ground reaction force, rate of force development and power (measured with a force plate) to give us information that we can use to evaluate the athlete for the symmetry of kinetics and movement control between sides during:
- bilateral testing (i.e. a squat jump performed on both legs),
- single leg hop,
- drop jump,
- single leg drop hop,
- reactive drop jump,
- reactive drop hop,
- bilateral pent jump, and
- pent jump.
Note athletes that are more reactive will have high RSI values, where their ground contact times will be less than 250ms (which depends on the task), the joint range of motion at the hip and knee will be very small thereby displaying high levels of stiffness (which is the resistance to deformation), and they will have high displacements despite short ground contact times and very little knee and hip bend. This quality could be the single most important determinant we’ve seen at predicting sport performance. All this said, the reactive symmetry between sides is critical during single leg tasks as well as bilateral task. Asymmetries are correlated with injuries and return to play protocols need to normalize discrepancies before return to competition. In the later, this is rarely the case and reflects our high reoccurrence rates of severe injuries such as ACL ruptures and the prevalence of Jumper’s Knee.
Q2) With sprinting, relaxation is often talked about from a coaching standpoint. With much of the preparation exercises being explosive what do you do to encourage both raw power and refined movement? Getting people to relax during explosive activities is a coveted skill set.
Dr. Lam: For our athletes we talk about signal to noise. Signal represents the impulse or a sharp contraction that is fast and precise. Noise represents all the extra muscular activity. To help our athletes understand signal and noise, or contract-relaxation, one example would be oscillation squats, coupled with plyometrics. During oscillations squats the athlete lowers themselves to a near parallel squat position. From this position they burst quickly moving the weight into a quarter squat position. Once at the quarter squat position they relax and descend back to a parallel position as quickly as possible and then they repeat this process for several reps that are part of a cluster. At the top portion of the rep we get to hear bar chatter – which is one of our favorite noises. We find the timing of this contraction-relaxation to be very effective in teaching athletes rhythm and how to use momentum, especially with weight. The weight is a key ingredient because it helps teach the athlete to be aligned, appropriately braced and relaxed in their power generators.
Now the plyometrics we couple with the oscillation squats include, two small jumps to one large jump, or various single leg hops and bounds (we also select multiple plane movement for athletes that need to cut and change directions). I’ll describe two small jumps to one large jump. During this exercise the athlete will perform two small jumps followed by a large jump. The main emphasis of this drill is to go vertical so there is little horizontal translation. The key cues we use are:
- no deformation (the knees should not bend much)
- crisp ball of the foot contact
- preactivation (activate the muscles responsible to jump before you make contact with the ground).
The cyclical nature of the two small jumps to one large jump helps the athlete feel an impulse followed by relaxation when in the air. Remember we’re looking to help an athlete understand signal to noise and how to relax after they’ve created an impulse. When we couple these exercise we find dramatic improvements in how the athlete learns how to contract and relax.
Signal to noise is a critical athletic quality to develop.
Q3) Soccer athletes are competing more and more and we are seeing this trickle down to the youth level. With speed being so valuable, how can we use simple jump testing and other monitoring tools to keep athletes that are talented and fast from being run into the ground?
Dr. Lam: Power is very sensitive to training readiness. When an athletes’ performance of power and reactiveness dips, this may be an indication that they are neurologically fatigued. One of our favorite tests we like to use is a 5 reactive jump test. During this test we measure flight time and ground contact time for each jump. The average ground contact time and flight time across the 5 tests is calculated to give us a metric to see the reactiveness of the athlete. When an athlete is fatigued their ground contact times will increase. We like to see ground contact times less than 200ms. This is based on Dietmar Schmidtbleicher work that classifies short / fast ground contact times as less than 250ms and those greater are regarded as long / slow.
Flight times can either increase or decrease because they are using a different strategy other than reactiveness to jump. The sensitivity of ground contact across the 5 tests is very important and it’s an example of one simple jump test that can help monitor an athletes’ training readiness. Of course there are many tests that can be used with varying sensitivities, reliabilities and research support.
I think the choice of any test or battery needs to help the coach / practitioner identify the training readiness (which spans qualities such as neurological readiness, physiological readiness, mental readiness, and cognitive readiness) and the health status of the athlete (tendon health, joint health, soft tissue health, etc.). There is no gold standard battery or any single test. Paying attention to the subtle signs when an athlete warms up and how they arrive at practice may be some of the best indicators that elite coaches use to evaluate an athletes’ state. Patterns will emerge.
Q4) No mystery that many athletes at World Championships are not even there because of injuries and illness. Besides harder surfaces, longer flights, and just "bad luck", why is this happening in your mind? What are your thoughts on gait analysis helping find problems early instead of defusing a bomb that already went off?
Dr. Lam: Long term athletic development is critical. The silent killer of athleticism is poor movement control. Likewise injuries don’t exclusively happen by chance. Athletes are a by product of movement control and the amount of exposure they have. If they have great control they can tolerate more exposure (games and practices), if they have poor control they can’t tolerate as much exposure without exceeding the tissue tolerance to become symptomatic. It’s amazing that our work with elite athletes has shown that many elite athletes, by definition by their world rankings may be the greatest compensators. They have movement control errors that have developed from years of using that strategy. Picking up movement control errors seemingly is very important, but what is relevant, is an important question.
The answer is, we don’t know.
Of course there are many factors to consider, such as age, weight, sport played and symptomology to evaluate whether a particular control error is relevant. We are only at the infancy in this knowledge, although a wealth of information has been published that links particular movement patterns with injury – such as delayed muscle activation and low back pain and ACL Ruptures, frontal and sagittal knee plane control for jumper’s knee and patellofemoral knee pain, and scapular control for shoulder impingement. Gait analysis is very tricky to understand. For example what is the relevance of flat feet, or pes planus during gait. It was once thought that pes planus would rob athletes of speed and explosiveness because the foot is too sloppy. Low dye tape jobs, orthotics, and footwear were designed to mitigate medial arch collapse without success. We can safely say today, that pes planus is not a death sentence for an athlete. Many of the fastest people on the planet have pes planus.
All this said, I’m a firm believer in early detection, but what do we focus on and what is relevant?
Q5) Many sprinters look at the weight room for developing speed and force plates are popular in some circles. What are your thoughts on some of the problems with looking at jumps only for power, isn’t their more beyond force curves? Perhaps sharing what you do in running mechanics and jumping technique?
Reactive abilities are beyond force curve, because they involve the storage and release of energy. They involve how we use momentum to increase our subsequent force output. Likewise, how we produce force is equally as important as what the ground sees. We call this the black-box effect. During combine testing, let’s say vertical jump, we only report how high the athletes jumps. But how the athlete jumps is very important, for example did the athletes’ knee move inwards (dynamic valgus) or did their pelvis shift towards one side. These compensations represent leaks in the system that help us identify areas that need improved control, that if corrected will improve performance.
Isn’t this the ultimate goal of training? What we choose to measure is critical because it has to be aligned with our approach to performance enhance, which includes injury prevention and injury resolution. The great realization about the continuum between injury prevention to athletic performance is that there isn’t a continuum. We really should be doing both at the same time. Force production at the ground is important but it’s not the only thing to consider. We already talked about energy leaks, but how the athlete sequences various areas of their body to produce power is also very important. In the example of vertical jump, we have 3 power determinants – leg power, hip and low back extension, and arm power.
These areas must be coordinated in a manner that summates the power derived from the other areas, much like throwing a baseball, where the power from the legs is channeled through the trunk, into the shoulder, into the elbow, into the wrist, and finally into the fingers and into the release of the ball. This process is called kinematic sequencing and if done properly is responsible for amazing feats of athleticism. Other important aspect to consider also include movement consistency, movement robustness, stiffness, force couples, relaxation, and timing and coordination.