Strength Training Form Check: 8 Most Common Technical Errors for Endurance Athletes

Movement Quality Determines Everything

For endurance athletes, the purpose of strength training is to improve performance and prevent injury—but only if the movement is correct. Poor technique not only diminishes training results, it can also create new injuries where you were trying to prevent them. Here are the 8 most common mistakes coaches see, along with their fixes.

Mistake 1: Knee Valgus in the Squat

The knees collapsing inward during the descent or ascent places enormous stress on the knee joint and patella, and is the most dreaded movement pattern for runners and cyclists.

Fix: Place a looped resistance band around the knees and actively push the knees toward the toes; strengthen the gluteus medius (lateral walks, single-leg bridges).

Mistake 2: Rounded Back in Deadlift/RDL

Using lumbar flexion instead of a hip hinge to complete the movement is the number one cause of lower back injuries.

Fix: Learn the hip hinge—place a stick against the back of your head, upper back, and sacrum; keep all three points in contact with the stick as you push the hips back; reduce the weight and build the pattern first.

Mistake 3: Measuring the Plank by Duration Instead of Quality

A sloppy 5-minute plank with a sagging pelvis and overextended lumbar spine is inferior to a perfect 45-second plank.

Fix: Shorten the duration; actively brace the glutes and core throughout, tilt the pelvis posteriorly, and tuck the ribs down; stop immediately when quality breaks down.

Mistake 4: Using the Same Weight and Reps for Every Movement

Doing 3×12 all year with no maximal strength phase means insufficient neural adaptation—this is the biggest reason amateur athletes see poor results.

Fix: Periodize—high reps during the anatomical adaptation phase, heavy loads at 3–6 reps during the maximal strength phase, and low-volume high-intensity work during the competitive season.

Mistake 5: Skipping Progression and Going Straight to Depth Jumps in Plyometrics

A common cause of Achilles and patellar tendon injuries is skipping the low-box and quiet-landing foundation and going straight to high-box depth jumps.

Fix: Strictly follow the progression—spend at least 2–3 weeks on low boxes and hops during the preparatory phase, then progress gradually; aim for quiet landings.

Mistake 6: Never Training Unilateral Movements

Double-leg squats mask left-right asymmetries, yet cycling and running are both unilateral, alternating movements.

Fix: Include rear-foot-elevated split squats, single-leg RDLs, and single-leg glute bridges in your program to actively expose and correct asymmetries.

Mistake 7: Still Doing Heavy Loads or High Eccentric Volume Before Competition

Delayed onset muscle soreness leaves your legs heavy on race day and degrades movement quality.

Fix: Stop soreness-inducing training 7–10 days before competition; keep only very low-volume, high-intensity “neural activation” work.

Mistake 8: Training Only Concentric Crunches and Ignoring Anti-Movement

Doing thousands of sit-ups while your pelvis still wobbles on the bike, because you lack anti-rotation/anti-lateral-flexion training.

Fix: Make “anti-movement” exercises—Pallof press, dead bug, side plank, farmer’s carry—the core of your training.

Quick-Reference Mistake Chart

“I would rather see an athlete perform a perfect squat with an empty bar than watch them do a heavy squat with knee valgus and a rounded back. In strength training, technique always precedes load—this isn’t conservatism, it’s the prerequisite for making training truly work for you.”

Whether strength training becomes a boost to endurance performance or a source of injury often comes down to these technical details. Regularly film yourself to review your movement, seek qualified coaching when necessary, and eliminate these 8 mistakes one by one—only then will every session truly count.

Related Reading

• Injury Prevention Training for Endurance Athletes: Ten Key Movements to Protect Your Career
• Strength Training Biomechanics: Why “Form” Matters More Than “Weight”
• How Weight Training Makes You Run Faster and Ride Stronger: Three Pathways—Neural, Tendon, and Economy
• Maximal Strength vs. Muscular Endurance Training: Which Lifting Mode Should Endurance Athletes Choose