The Claim
In healthy adult women, carrying an additional load of 20.4 kg (representing 23–36% of body weight) is associated with a 24–43% increase in quadriceps electromyographic (EMG) activity during early stance phase of gait and a 25–32% increase in plantarflexor EMG activity, with minimal changes in ankle and knee joint kinematics, suggesting that the primary effect of added load is increased extensor muscle activation rather than alterations in lower limb joint motion.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
When healthy women carry a heavy backpack—like 20 to 30 pounds—their leg muscles have to work a lot harder, especially the quads and calf muscles, but their walking motion stays pretty much the same.
See the scientific wording
In healthy adult women, carrying an additional 20.4 kg (23–36% bodyweight) is associated with a 24–43% increase in quadriceps EMG during early stance and a 25–32% increase in plantarflexor EMG, but minimal changes in ankle and knee joint motion, suggesting that added load primarily increases extensor muscle activation without substantially altering lower limb kinematics.
What the research says
1 studyThe study found that when people walk with extra weight, their leg muscles work harder, especially at the start of each step, but their walking motion stays mostly the same, which matches the claim.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.