Effects of Light-Emitting Diode Therapy on Muscle Hypertrophy, Gene Expression, Performance, Damage, and Delayed-Onset Muscle Soreness: Case-control Study with a Pair of Identical Twins.
Cleber Ferraresi, Danilo Bertucci, Josiane Schiavinato and 9 others
PMID 27088469WHAT IT FOUND
Adding LED therapy to the same strength training in two identical twins was associated with greater leg press and leg extension loads, larger thigh muscle volume, less soreness and smaller increases in a blood marker of muscle damage than adding placebo.
Only two people.
Key findings
01Both twins did the same 12-week strength training; the twin randomized to LED therapy had leg press 1RM go from 320 to 490 kg and leg extension 1RM go from 60 to 82.5 kg, while the placebo twin had leg press 1RM go from 320 to 410 kg and leg extension 1RM go from 62.5 to 75 kg.
02After the 1st, 13th, 25th, and 36th training sessions, the LED therapy twin reported lower pain on a 10 cm visual analog scale than the placebo twin: 5.5 versus 8.2, 1.4 versus 3.2, 0.4 versus 1.8, and 0.3 versus 1.0.
03Thigh muscle volume measured by MRI increased from 2937 to 3523 cm 3 in the LED therapy twin and from 3152 to 3316 cm 3 in the placebo twin.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The study had only two participants. Both twins received the same 12-week strength training, so the study compares adding LED therapy with adding placebo to training, not LED therapy alone or training alone. The supplied text does not name a primary outcome, and it does not report statistical tests or confidence intervals for the differences. The participants were two 19-year-old male college soccer players living together with the same habits and diet. The LED device was a research prototype built for the study.
The easy way to misread this
Do not conclude that LED therapy improves muscle strength, hypertrophy, soreness, creatine kinase, or gene expression in patients. The study had only two identical twins, both received the same 12-week strength training, and the supplied text does not name a primary outcome, so the results are descriptive comparisons between one twin and the other.