Can't Straighten Your Arms After Lifting Weights? Here's What Your Body Is Trying to Tell You

Delayed-onset muscle soreness may cause you to be unable to straighten your arms after lifting weights.
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The day after a tough upper-body workout, you may find you're not able to fully extend your arms. Muscle exhaustion and soreness are normal after a challenging weight-lifting workout, but the symptoms should resolve within a couple of days if you invest some time in TLC.

But also, if you're lifting weights that are too heavy for your current ability level or lifting with improper form, it can lead to injury. And if pain and lack of joint mobility continue, it may be a sign of a more serious condition or injury.

If any of this sounds like you, keep reading to figure out what your body might be trying to tell you.

Tip

If you can't straighten your arms after a weight-lifting workout, it might be the result of normal muscle soreness. But if the pain is severe, doesn't improve or you have swelling in your joint, consult your doctor as it may be a more serious condition such as a tendon injury or rhabdomyolysis.

1. Your Muscles Are Sore

Delayed-onset muscle soreness, or DOMS, is the normal muscle soreness you experience after a hard workout, especially if you're introducing new exercises or increasing the intensity of your training, according to the American College of Sports Medicine.

While the specific cause of DOMS is unproven, research (like the often-cited August 1992 article from the ​Journal of Strength and Conditioning Research​) suggests that it's caused by the microtears to the muscle fibers that happens when you stress your muscles (like you do when you lift weights).

The severity of post-exercise muscle soreness depends on weight-lifting intensity and fitness level. It usually starts the day after your workout and resolves itself within a few days. If the soreness is severe enough, you may find you can't extend your arm after the workout.

Fix It

During your recovery (24 to 72 hours), don't perform strenuous weight-lifting workouts on the same muscle group, but be sure to keep moving.

Gentle exercise (like walking or cycling) and stretching can help reduce discomfort and speed up your recovery. Light massage, using a foam roller and applying cold to the sore muscles may also help.

2. You're Doing Too Many Reps or Your Form Is Off

Doing the same motion over and over again — particularly if you're doing it incorrectly — can irritate your tendons (the connective tissue that's found between muscles and bones) and cause irritation.

Particularly, if you can't straighten your arm, it may be medial epicondylitis (aka golfer's elbow), according to the Mayo Clinic. Symptoms include pain on the inside of your elbow, stiffness, numbness and weakness in the wrist and hands.

Fix It

Consult your doctor if you think you have golfer's elbow or any other tendon inflammation or injury. Treatment options include pain medications, rest and ice. Wearing an elbow brace may help reduce further strain on the elbow.

3. You May Be Working Out Too Hard

If you work out too hard or have other underlying issues, such as low phosphate levels, injuries or dehydration, you may experience a severe condition called rhabdomyolysis, according to the US National Library of Medicine.

This condition occurs when the muscle fibers break down and enter the blood stream, leading to kidney damage. In addition to muscle soreness and joint pain, you may experience dark urine, decreased urination and fatigue. Consult your doctor immediately if you experience these symptoms.

Fix It

Stop it from even happening in the first place. Lifting weights with improper form is likely to lead to injury. Consider working with a personal trainer to learn correct movements and establish a workout routine appropriate for your fitness level.

You should increase the intensity of your workouts and the amount of weight you lift slowly and be sure to warm up before your workouts and cool down afterward to prevent extreme soreness and injury.

When to See a Doctor

Although muscle soreness is normal, other serious conditions and injuries may also cause you to be unable to straighten your arm after lifting weights. Exercise statistics show 21.5 percent of active adults report an injury in the last 12 months, according to a December 2018 study in ​​Injury Epidemiology​​.

Consult your doctor if you experience symptoms such as:

  • Pain or swelling in the joints
  • Pain that begins suddenly during exercise
  • Muscle soreness that doesn't begin to improve after 48 hours
  • Dark urine or decreased urination
  • Fever
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