The TheraBand FlexBar is a flexible rubber resistance bar used primarily to treat tennis elbow and golfer’s elbow through a specific twisting exercise. It works by loading the injured forearm tendons eccentrically, meaning the muscle lengthens under tension rather than shortening. This type of loading is one of the most effective rehab strategies for tendon pain. The bar comes in four color-coded resistance levels, and the core exercises take only a few minutes per session.
Choosing the Right Resistance Level
Each FlexBar color corresponds to the force needed to bend it into a U-shape:
- Yellow: 6 pounds of force (extra light)
- Red: 10 pounds of force (light)
- Green: 15 pounds of force (medium)
- Blue: 25 pounds of force (heavy)
Most people recovering from elbow tendon pain start with the red bar. If you’re in an early or acute stage and the red feels too difficult, drop to yellow. The ridged surface helps with grip, but the twist should feel challenging without causing sharp pain. Once you can complete a full session comfortably, move up to the next color.
The Tyler Twist for Tennis Elbow
Tennis elbow (lateral epicondylitis) causes pain on the outer side of the elbow, where the wrist extensor tendons attach. The Tyler Twist is the signature FlexBar exercise for this condition, published in a study from the Journal of Orthopaedic & Sports Physical Therapy that showed significant pain reduction and strength gains. Here’s how to do it, step by step. These instructions assume your right arm is the injured side; reverse everything if it’s your left.
Hold the FlexBar vertically in your right (injured) hand with your wrist extended back, knuckles pointing toward the ceiling. Grab the top end of the bar with your left (uninjured) hand. Now twist the bar with your left wrist, like wringing out a towel, while keeping your right wrist locked in extension. This is the loading step, and your uninjured hand does all the work here.
With the bar now twisted and loaded, bring both arms straight out in front of your body, elbows fully extended, and hold the bar horizontally. Your left wrist should be in full flexion (curled down) and your right wrist still extended (curled up). This is your starting position for the eccentric phase.
Slowly allow the bar to untwist by letting your right wrist move down into flexion. This controlled “unwinding” is the therapeutic part of the exercise. Your injured forearm extensors are lengthening under load, which stimulates tendon healing. The untwist should take about four seconds. Don’t let the bar snap back quickly.
The Reverse Tyler Twist for Golfer’s Elbow
Golfer’s elbow (medial epicondylitis) causes pain on the inner side of the elbow, where the wrist flexor tendons attach. The Reverse Tyler Twist targets these muscles by flipping the movement. Instead of eccentrically loading the extensors, you’re loading the flexors.
Grip the FlexBar with your injured hand in the starting position with your wrist flexed (curled toward your palm). Use your other hand to twist the bar into a loaded position. Then slowly allow the bar to untwist by letting your injured wrist extend (uncurl). Keep your elbows close to your body and your wrists controlled throughout the movement. The slow, controlled unwind over three to six seconds is what delivers the eccentric load to the injured tendons.
Sets, Reps, and Frequency
Clinical protocols typically use 3 sets of 15 repetitions per session, performed 5 days per week. Each repetition takes about four seconds for the eccentric phase, with a 30-second rest between sets. A full session takes roughly 10 to 12 minutes. In published studies, this protocol ran for six weeks, which is a reasonable timeline to expect noticeable improvement.
Some mild discomfort during the exercise is normal, especially in the first week or two. A useful rule of thumb: if the pain stays below a 4 out of 10 during the exercise and doesn’t linger afterward, you’re in a safe range. If the exercise causes sharp or worsening pain, drop to a lighter bar or reduce your reps and build back up gradually.
Grip and Wrist Strengthening Exercises
Beyond the twist protocols, the FlexBar works well for general forearm conditioning. One simple exercise is the FlexBar shake, sometimes called oscillation. Hold the bar vertically with one hand and whip it back and forth rapidly, creating a vibrating motion. This builds wrist and forearm endurance, and the intensity is entirely self-controlled: grip harder and whip faster to increase the challenge, or ease up when you’re fatiguing. This is often one of the first exercises given for early-stage wrist or elbow tendonitis before progressing to the full twist protocols.
You can also use the FlexBar for basic grip strengthening by squeezing it in different hand positions, or for thumb opposition exercises by pressing against its surface. These are useful for general hand and forearm rehab, particularly for people returning to activities that demand sustained grip, like rock climbing, racquet sports, or manual trades.
Tips for Getting the Most Out of It
The eccentric phase is the entire point. If you rush through the untwist, you’re missing the benefit. Focus on a slow, controlled release every single rep. It helps to count to four in your head as the bar unwinds.
Consistency matters more than intensity. Doing 3 sets of 15 reps five days a week for six weeks will produce better results than sporadic sessions with a heavier bar. If you miss a day, just pick up where you left off.
Progress to a heavier bar when your current one feels easy for the full 3 sets of 15. Most people move through one or two color progressions over the course of their rehab. There’s no rush to jump to the blue bar. The goal is controlled, pain-free loading that gradually increases over weeks.