Force Plate Testing and Overhead Athletes

Hey team!

Thank you for reading part 1 of this 3 series blog post on shoulder testing using handheld dynamometry and force plate testing.

 I’m even more excited to share part 2 and 3 with you where we’ll cover force plate testing and the upper limb, but before I get into it, I wanted to share my journey of how I got interested in using force plates.

I have worked in national and international-level baseball for over 13 years now. I work with the Adelaide Giants (ABL) who were back-to-back champions in 2022/23 and 2023/24. I am also fortunate enough to work with Team Australia (juniors and senior teams).

Three years ago, I read Aiden Oakley’s blog post on upper body assessment which got the ball rolling to motivate me to level up my shoulder game. At the same time, my colleagues at the Wakefield Sports & Exercise Medicine Clinic in Adelaide, South Australia, who specialize in ACL Management had a more robust testing battery to help return their athletes back to sport. This is where the shoulder return to sport battery of testing was lacking.

Enter the Director of Asia Pacific for Hawkin Dynamics (HD), James Hanisch, who I reached out to so I could learn more about the HD force plates. It didn’t take long for me to fall in love with the simplicity and reliability of these plates, which matched James’ customer service and support from day one. I purchased my HD plates and have never looked back.

Enough about me and James, as I have digressed. Let’s get back into force plate testing for overhead athletes.

The key tests I am using for my overhead athletes are:

• ASH (athletic shoulder) test
  

   

   (ASH I-180)

  
  
  (ASH Y)
  

  (ASH T)

  (ASH I-0)

• Countermovement Push Up (CMPU)

  
  
  
  
• Press Jump
  
  
  
  
  
• Box Drop Land

Here are some of my tips on how to implement force plates with overhead athletes.

 1. Baseline/Pre-season Assessment is Key:

Before an overhead athlete embarks on a rigorous training program, it's crucial to establish a baseline using force plate testing. This helps me understand their unique movement patterns (actually watch the athlete doing the test, not just the tablet with the data output 🤦‍♂️), identify any imbalance (peak force, rate of force development (RFD), time to peak force), and assess how they distribute force during different activities. It's like creating a roadmap for personalized and effective training.

Overhead athletes such as throwers will be stronger on their dominant sides. Monitoring their pre-season scores whilst in season or when returning from injury can give you key insights as to how their shoulder is tolerating the load placed upon it. From my experience, a reduction in peak force of > 30% following a training session or game tells me that something isn’t right or competing might just be causing them to be paying too high of a price.

 2. Sports-specific Positions:

Overhead athletes, with their complex movements, require dynamic stability. Force plate testing allows us to simulate sport-specific positions to try to replicate what they do in sporting situations. This insight helps tailor exercises that mimic their sports-specific demands, enhancing their overall performance and reducing the risk of injuries.

Overhead athletes may have different arm slots when throwing or hitting a ball. This is where the ASH test allows us to test the athlete in a variety of arm angles that may be relevant to them and their sport. We are testing their system’s ability to produce force in a long lever position whilst visually monitoring what the trunk is doing to help transfer the kinetic energy. Common compensatory strategies are:

•  Bending the elbow to shorten the lever of the arm

• Anteriorly tilting scapular
• Trunk rotation

•  Hip/leg abduction - A must-do test for all your overhead athletes!

Shoulder injuries are common among overhead athletes, and load management is crucial. Force plate testing helps us quantify the forces acting on the body during various movements and isometric tasks. By understanding these loads, we can fine-tune training programs to ensure optimal strengthening without overloading vulnerable structures, thus preventing overuse injuries.

Over the last few years, I have been looking at the dynamic strength index (DSI) for ASH test T position vs CMPU but I’m still awaiting a larger sample size to determine if there is a similar pattern to what we see in the lower limb DSI taken from the isometric mid-thigh pull and countermovement jump tests… so watch this space in future!

Max test graph (above) - max effort, push into the plate as fast and hard as you can

4. Rehabilitation Progress Tracking:

For athletes recovering from shoulder injuries, force plate testing becomes a valuable tool for tracking rehabilitation progress. It allows us to objectively measure improvements in peak force production, power output, RFD, braking and propulsive impulse (force over time), landing impulse or time to stabilization, time to peak force, and overall functional performance. This not only boosts the athlete's confidence but also guides us in making necessary adjustments to the rehab plan.

There is still a growing body of evidence in this space whilst there isn’t too much normative data published, yet. This is an emerging and exciting space in sports medicine. I am not convinced we have a clear model for injury prediction of shoulder injuries, but if force plate testing gives us a lot of metrics and sports-specific functional performance outcome measures to track over time. This allows us to test patients against themselves or their teams.

4. Customized Training Protocols:

Force plate data provides a personalized approach to training. By analyzing an athlete's force distribution between limbs. This tailored approach optimizes performance and also plays a crucial role in injury prevention, aligning with our goal of keeping our overhead athletes in the game for the long run.

Know what testing metrics matter, know what to test for your athlete and their sport, then know what target exercises you can implement based on their sub-optimal testing scores, and finally, highlight and indicate their areas of room for improvement. 

Remember, force plate testing is not just about numbers; it's about translating that data into actionable insights for a holistic approach to athlete care. Watch your athletes to ensure they are completing each test with good quality of movement, by not just staring at the tablet… use your clinical reasoning to marry up what you see and what they score in the HD cloud!

The next two blog posts will discuss how to implement force plate testing within the clinic, not just with my athletes.

See you in the next blog post 💪

ABOUT BEN ONOFRIO

Ben helps allied health clinicians improve their knowledge and confidence when it comes to assessing and managing shoulder injuries, so they can avoid burnout, save their thumbs, and be seen as the expert!

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