Strength Training Safety Sheet

Safety Status:

Trying to Conceive: Safe
Pregnancy: Limited
Postpartum: Limited

What We Know: Strength training encompasses resistance exercises using free weights, machines, resistance bands, or body weight to improve muscular strength, endurance, and power. This category includes traditional weight lifting, resistance training, and targeted muscle group exercises.

For individuals trying to conceive, strength training is generally considered safe and potentially beneficial. The American Society for Reproductive Medicine supports moderate-intensity exercise during the conception period, including appropriately designed strength training programs. Research published in Sports Medicine indicates that regular strength training may help maintain healthy body composition and hormonal balance, factors that support fertility in both men and women. However, extremely heavy lifting or training to muscular failure could potentially impact hormonal profiles in some individuals, suggesting moderation for those actively trying to conceive.

During pregnancy, strength training receives a “Limited” classification requiring modifications as pregnancy progresses. The American College of Obstetricians and Gynecologists (ACOG) supports strength training during pregnancy but recommends reducing resistance and avoiding exercises in the supine position after 20 weeks. A 2021 systematic review in the British Journal of Sports Medicine found that supervised, moderate-intensity resistance training during pregnancy can be safe and beneficial for maternal health outcomes. Key pregnancy modifications include:

1. Decreasing weight and increasing repetitions as pregnancy progresses
2. Avoiding the Valsalva maneuver (holding breath during exertion)
3. Using machines rather than free weights in later pregnancy to reduce fall risk
4. Eliminating exercises that place direct pressure on the abdomen
5. Avoiding exercises performed lying flat on the back after the first trimester
6. Modifying stance and positioning to accommodate the changing center of gravity

For postpartum individuals, strength training also receives a “Limited” classification with return timing depending on delivery type and individual recovery. According to guidance from the Section on Women’s Health of the American Physical Therapy Association, resistance training can begin with gentle bodyweight exercises as early as 2-3 weeks postpartum for uncomplicated deliveries, but heavier loads should be reintroduced gradually after pelvic floor healing is well-established, typically not before 6-8 weeks postpartum.

Specific postpartum considerations for strength training include:

1. Research in the Journal of Women’s Health Physical Therapy indicates that exercises creating high intra-abdominal pressure should be modified until pelvic floor function is restored
2. Progressive loading is essential, beginning with bodyweight or very light resistance before gradually increasing
3. Proper breathing techniques should be emphasized to avoid creating excessive pressure on the pelvic floor
4. Exercises that target diastasis recti recovery should precede traditional core strengthening
5. For cesarean deliveries, exercises that strain the abdominal incision should be avoided until at least 8-12 weeks postpartum, with progressive return based on healing status

The 2019 Canadian guideline on postpartum exercise recommends individualized assessment of pelvic floor function before returning to heavy lifting, noting that even among women without symptoms, over 50% show reduced pelvic floor muscle function on assessment at 6 weeks postpartum.

Sources: American College of Obstetricians and Gynecologists (ACOG) Committee Opinion No. 804; British Journal of Sports Medicine Systematic Reviews; Section on Women’s Health, American Physical Therapy Association Clinical Practice Guidelines; Journal of Women’s Health Physical Therapy research on pelvic floor recovery; Canadian Guideline for Physical Activity throughout Pregnancy and Postpartum