Grip Strength: Why It Matters For Your Shoulder The shoulder is a complex joint that involves many different structures and motions. It is the connection between the upper limb and torso and is highly involved in many sports/activities. This also means that it is an area that is often injured within athletic populations, including those participating in regular resistance training. It has been estimated that up to 36% of resistance training related injuries involve the shoulder complex (1). These injuries have a broad range with regards to the specific structures being affected, the type of injury, and the specific mechanisms causing the injury. These cannot only impact your performance in activities/gym, but also in your daily life.   So why does grip strength matter?  Grip strength has been shown to correlate with overall function of the shoulder. A study by Antony et al found an increase in shoulder muscle activity (increased shoulder stabilizer activation, decreased activation of compensatory muscles – anterior/middle deltoid) occurred when the amount of force used to grip increased (2). This basically means that if you squeeze your hand harder, there will be increased muscle activity in muscles that help stabilize the shoulder. Another study by Horsley et al, looked at the connection between grip strength and rotator cuff strength in healthy individuals. They found there was increased strength the rotator cuff in individuals that had higher grip strength (3). Try this!   Place your right arm at your side and your left hand on your right shoulder. You can hold onto an object, or just make a fist with your right hand.  Start to squeeze the right hand, slowly ramping up the strength till a max contraction.  You will notice that as you start to increase the strength of the contraction, the muscle activation starts to increase in the shoulder (you should feel the muscles in the arm/shoulder fire).  There have been several proposed reasons for this relationship. One involves the concept of irradiation, which entails the transmission of neural impulses from a contracting muscle to the surrounding muscles. This will not only increase the activation of the surrounding muscles, but also increase their strength output (if they are involved in the action). Another theory is that the tension/forces are transmitted via myofascial/myotendinous expansions running up the arm, providing a network for this transmission (4).   What makes up grip strength?  Most people believe that overall grip strength is purely produced by the flexors of the forearm (muscles responsible for closing the hand). But it is actually also involves the extensors of the wrist/hand (muscles that open the hand). These will act as an opposing force to the flexors to help create functional stability of the joint (4). How can this help me? Try incorporating exercises that involve the use of grip strength (carry variations, Kettle Bell “bottoms-up” presses, 1-arm hangs, etc.) into your routine. It can be beneficial to not only build muscle, but also increase grip strength.   Suitcase Carry Kettle Bell "Bottoms Up" Press Grip strength alone is not the cure for all shoulder injuries! There are many different factors to consider for each individual case and injury; this is just a small piece of a much bigger puzzle. This post is meant to shed light on an often overlooked area when it comes to shoulder health and function. If you are experiencing any shoulder pain or would like to work on preventing future shoulder issues, feel free to contact me and we can go over some options for you.    Written by Dr. Jon Perry Chiropractor 1. Kolber, M. J., Beekhuizen, K. S., Cheng, M. S. S., & Hellman, M. A. (2010). Shoulder injuries attributed to resistance training: a brief review. The Journal of Strength & Conditioning Research, 24(6), 1696-1704. 2. Antony, N. T., & Keir, P. J. (2010). Effects of posture, movement and hand load on shoulder muscle activity. Journal of Electromyography and Kinesiology, 20(2), 191-198. 3. Horsley, I., Herrington, L., Hoyle, R., Prescott, E., & Bellamy, N. (2016). Do changes in hand grip strength correlate with shoulder rotator cuff function?. Shoulder & elbow, 8(2), 124-129. 4. Robb, A., Weinberg, B. Athletic Movement Assessment Manual (Taken June 24-25, 2017).

Train Like an Athlete:

PAP Training for Sprinting and Jumping

Often with general-population fitness enthusiasts, our goals are centered around looking good, moving better, and staying healthy. However, for those of us who enjoy a good Catalyst Challenge, play a sport, or get a little competitive with themselves, training focused on improving strength and power performance is paramount to long-term success in your athletic endeavors.  PAP (or Post-Activation Potentiation) combines strength and power training into one workout using specific percentages of your maximum strength in a given exercise, rest times just long enough to fully replenish your ability to be explosive, and an applicable power exercise to your given sport or activity not for your beginner or novice gym goer best and most safely utilized by someone who has experience training at high loads and high speeds.

Step 1: Heavy Movement      PAP training starts with a “conditioning activity” as it’s referred to in the scientific literature. This does not refer to time on the rower or the ski erg, but an activity of significantly high loading to “condition” the body to be prepared for what is to come. This is typically a heavy compound movement such as a barbell squat, deadlift, or bench press (7).  Better performance is seen using heavier loads of up to 90% of your 1 repetition max for 1-3 reps (4). This is why PAP is only suited for advanced athletes and gym goers – you must be skilled and strong in order to benefit from PAP (11)(10).  It is best to pick a movement that applies to your chosen power activity for step 3. For example: A heavy squat paired with a jump, a deadlift paired with a sprint, or even a weighted pull-up paired with a short ski erg sprint.

Step 2: Rest      It’s really important to rest enough during PAP training. While you may not be breathing hard, your body goes through a period of fatigue and adaptation after your heavy set in step 1.  The general rule is the more volume (or number of reps) completed in step one, the more rest you get. Both upper and lower body rest times have been successfully tested at around 7-10min (11)(3), but very little difference is seen between 5-10-15-20min in terms of peak power output in step 3 (6).  My recommendation would be to take at least 5min rest, but if you are feeling fried there is no shame in resting longer if it means you work harder and perform better when step 3 comes (8)(9).

Step 3: Power Movement      The final selection is a power movement that applies to your sport (or Catalyst Challenge). If you play a field sport (soccer, football, ultimate frisbee) that requires you to intermittently sprint you may want to pick a 5-10m sprint as your power movement. 5-10m sprint times were improved in professional rugby players when they used 91% of their 1RM as their step 1 movement (1). If you play a court sport (basketball, volleyball, badminton) where you are required to jump high you may want to pick a counter-movement or vertical jump. A maximally loaded 3 rep back squat has been shown to significantly improve a vertical jump with individualized rest times (2).      Once step 3 is completed, you should take another rest period of at least 5min to replenish your ability to perform at maximum intensity before returning to step 1. The ability to perform at maximum intensity is the most important factor to this training, and is the reason why the rest breaks feel so long. By training with this method you will increase your sprint speed, jump height, or whatever explosive activity you aim it at. Use your best judgment, train smart, and train safe when using tools of the caliber.

Written By:  Phil Tungate Strength and Conditioning Specialist