The Exercise Your Athlete's Bodies are Begging For (And Nobody's Teaching Them)

What is isometric training, what it actually does to muscles and tendons, and why it's one of the safest strength training and athletic performance tools for growing athletes in Pittsburgh.

Short answer for the busy parent: Isometrics: holding a muscle contraction at a fixed joint angle, no movement, just tension. These types of exercises are one of the safest, most evidence-backed strength tools available for growing athletes. They build tendon resilience, teach the nervous system to produce force without the joint stress of heavy dynamic lifting or the pounding of plyometrics, and they're even used clinically to knock down tendon pain in-season. If your kid plays basketball, soccer, volleyball, softball, baseball, lacrosse, daces, cheers, or wrestles for a South Hills, Finleyville, Elizabeth, Trinity, Ringold, Peters Township, Canon-Mac, Upper St. Clair, South Fayette, or Bethel Park athletics program, this is a tool I use with almost every athlete who walks into ETE.

Let's get into why with the actual research behind it, not just coach-speak.

What Isometrics Actually Are (And Why They're Not "Just Standing There")

An isometric contraction happens when a muscle generates force but the joint angle doesn't change. Think wall sits, planks, a paused squat at 90 degrees, or a Spanish squat holding tension in the quad. No lengthening, no shortening, just controlled tension held for time.

To a parent watching from the sideline of a training session, it can look like the least impressive thing happening in the gym. That's exactly why it gets skipped by a lot of programs chasing flashy content for Instagram. But tissue doesn't care about aesthetics, it cares about load, and isometrics deliver a very specific, very controllable dose of it.

What Isometrics Do to Different Tissues

This is where it gets interesting, because isometrics don't affect muscle, tendon, and the nervous system the same way and that's actually the point.

Tendon: This Is Where Isometrics Shine

Tendon is slow to adapt and easy to overload, which is exactly why so many overuse injuries in young athletes, Osgood-Schlatter's, Sever's, patellar tendinopathy, "jumper's knee," show up at the muscle-tendon junction during growth spurts. Research out of the University of Tokyo found that 12 weeks of isometric training increased tendon stiffness significantly, while plyometric training did not produce the same tendon adaptation over the same period (Kubo et al., 2017). A related trial using the same 6-week isometric protocol in young men produced a 61.6% increase in Achilles tendon stiffness (Burgess et al., 2007) — a meaningful adaptation for athletes doing repetitive jumping, cutting, or sprinting.

Why does that matter for your athlete? A stiffer, more resilient tendon stores and returns elastic energy more efficiently and tolerates the repetitive loading of a full basketball or soccer season better than an undertrained one.

Pain and the Nervous System: The Clinical Case Is Strong

This is the finding that changed how sports medicine treats tendon pain. A landmark study out of Monash University found that a single bout of heavy isometric contraction (70–80% of maximum effort, held for 45 seconds, five sets) produced immediate, significant pain relief in athletes with patellar tendinopathy, pain relief that was still present 45 minutes later. The isotonic (regular up-and-down) exercise group didn't get the same effect (Rio et al., 2015). The mechanism appears to be a combination of pain modulation at the spinal cord level and increased muscle activation; meaning isometrics don't just mask pain, they seem to reduce the nervous system's pain "gain."

Clinically, this is why isometrics are often my first move with an athlete dealing with early tendon irritation. Instead of pulling them out of training entirely, a well-dosed isometric protocol can calm the tissue down while they stay engaged in their season.

Muscle: Strength Without the Aftermath

Because there's no eccentric (lengthening-under-load) component, isometrics don't produce the same degree of microtrauma and delayed onset muscle soreness that heavy eccentric or plyometric work does (Jamurtas et al., 2000). For a 13-year-old with practice the next

day, or a two-sport athlete juggling travel basketball and club soccer in the same week, that's a real advantage, you get a genuine strength stimulus without a multi-day recovery tax.

So Why Isometrics Instead of (or Alongside) Plyometrics and Heavy Lifting?

I want to be straight with you here: isometrics are not a replacement for a full strength and power program. Plyometrics build reactive tendon extensibility and rate of force development that isometrics don't replicate (Kubo et al., 2017), and progressive dynamic resistance training is still essential for long-term athletic development. This isn't an either/or it's about proper sequencing and exercise prescription.

Where isometrics earn their spot is:

• Early in a training block, to build a strength and tendon-stiffness base before we ask tissue to absorb jumping and cutting forces

• In-season, when recovery windows are tight and we need a training effect without extra soreness

• During growth spurts, when tendon strength typically lags behind bone and muscle growth (Mersmann et al., 2016), making this exact window the highest-risk period for tendon-related overuse injuries

• In rehab or "orange-light" situations, when an athlete has tendon irritation but we don't want them to lose an entire season sitting out

That last one is where my athletic training background comes in, sports medicine and sports performance aren't separate conversations here. The exercise that keeps a kid in the game safely is the performance exercise.

What This Looks Like for a Pittsburgh Athlete's Week

For a Pittsburgh area basketball or volleyball athlete mid-season, an isometric block might mean a 30–45 second wall sit or Spanish squat hold at high effort, two to three times a week, layered in alongside, not instead of, their sprint work, jumps, and dynamic lifting. For a younger athlete just starting structured training, isometrics are often where we begin, because they teach an athlete how to produce real tension and brace properly before we load movement on top of that.

This is also exactly why "no growth plate injuries in athletes engaged in an appropriately prescribed regimen" isn't a throwaway line, the appropriate prescription is the safety mechanism, and isometrics are one of the most controllable tools we have for delivering it.

Frequently Asked Questions

Are isometrics safe for youth athletes with open growth plates? Yes, when programmed and supervised appropriately. Isometrics involve no eccentric loading, no ballistic force, and no maximal-effort single reps — the loading variables most associated with injury risk in youth training. The broader research on youth resistance training shows injury risk is low and comparable to adult training when programs are properly designed and coached (Faigenbaum et al., 2009).

Can isometrics help with knee pain from basketball or volleyball (jumper's knee)? Isometric holds have been shown to produce immediate pain reduction in athletes with patellar tendinopathy, in some cases outperforming standard dynamic strength exercise for short-term pain relief (Rio et al., 2015). This makes isometrics a useful in-season tool for managing tendon irritation without a full stoppage of activity — always alongside guidance from a qualified clinician.

Do isometrics build real strength, or just "hold" strength? Both. Isometric training increases tendon stiffness and angle-specific muscular strength, and studies comparing isometric to plyometric training have found comparable gains in rate of force development and jump height over a training block (Lum & Barbosa, 2019).

Should isometrics replace plyometrics or weightlifting for my athlete? No — they complement each other. Isometrics build the tendon and strength foundation; plyometrics build reactive, elastic power; progressive resistance training builds overall strength and muscle capacity. A well-designed youth program uses all three, sequenced to the athlete's training age, sport demands, and time of year.

Laura Baden, LAT, ATC, OPE-C, CES, PES, is the founder of Earn the Edge Performance in the South Hills/Venetia area, where sports medicine meets sports performance for athletes

ages 9 and up.

References Burgess, K.E., et al. (2007).

Plyometric vs. isometric training influences on tendon properties and muscle output. Journal of Strength and Conditioning Research. Faigenbaum, A.D., et al. (2009).

Youth resistance training: Updated position statement paper from the National Strength and Conditioning Association. Journal of Strength and Conditioning Research, 23(5). Jamurtas, A.Z., et al. (2000).

Comparison between leg and arm eccentric exercises of the same relative intensity on indices of muscle damage. European Journal of Applied Physiology. Kubo, K., Ishigaki, T., & Ikebukuro, T. (2017).

Effects of plyometric and isometric training on muscle and tendon stiffness in vivo. Physiological Reports, 5(15), e13374. Lum, D., & Barbosa, T.M. (2019).

Brief review: Effects of isometric strength training on strength and dynamic performance. International Journal of Sports Medicine. Mersmann, F., et al. (2016).

Athletic training affects the uniformity of muscle and tendon adaptation during adolescence. Journal of Applied Physiology. Rio, E., Kidgell, D., Purdam, C., Gaida, J., Moseley, G.L., Pearce, A.J., & Cook, J. (2015).

Isometric exercise induces analgesia and reduces inhibition in patellar tendinopathy. British Journal of Sports Medicine, 49(19), 1277–1283.