Dehydration and symptoms of delayed-onset muscle soreness in normothermic men.
BACKGROUND
A dehydrated individual who performs eccentric exercise may exacerbate skeletal muscle damage, leading to structural, contractile, and enzymatic protein denaturation, in addition to the myofiber and connective damage resulting from the eccentric muscle tension.


OBJECTIVE
To identify the effects of dehydration on 5 physiologic characteristics of delayed-onset muscle soreness (DOMS) in normothermic men after an eccentric exercise perturbation.


METHODS
Randomized group test-retest design.


METHODS
Laboratory.


METHODS
Ten healthy male volunteers randomly assigned to either a euhydration (age = 26.2 +/- 4.9 years, height = 174.1 +/- 6.0 cm, mass = 86.5 +/- 15.3 kg) or dehydration (age = 25.8 +/- 2.2 years, height = 177.2 +/- 3.1 cm, mass = 84.4 +/- 3.8 kg) group.


METHODS
Subjects performed treadmill walking for 45 minutes in either a thermoneutral (euhydration) or a hot, humid (dehydration) environment. After a rest period to allow for return to the normothermic condition, DOMS was induced with a 45-minute downhill run.


METHODS
We assessed 5 physiologic characteristics of DOMS before and at intervals after the eccentric exercise. The characteristics were perceived pain of the bilateral quadriceps and overall body, bilateral punctate tenderness of the superficial quadriceps muscles, bilateral knee-flexion passive range of motion, bilateral thigh circumference, and bilateral isometric quadriceps muscle strength. Thermoregulatory and cardiovascular measures were obtained to monitor participants' heat load during exercise.


RESULTS
The experimental protocol produced a 0.9% increase in body mass of the euhydration group and a significant 2.7% decrease in body mass of the dehydration group. The downhill-running exercise perturbation induced DOMS in both the euhydrated and dehydrated participants, based on increased bilateral quadriceps and overall body perceived pain and punctate tenderness of the bilateral vastus medialis muscle. The signs and symptoms of DOMS after an eccentric exercise perturbation were not exacerbated by moderate dehydration of 2.7% body mass after rest and return to the normothermic condition.


CONCLUSIONS
Significantly dehydrated participants who rested and returned to a normothermic condition did not experience increased characteristics of DOMS.
Cleary
Michelle A
MA
Florida International University, Miami, FL 33199, USA. clearym@fiu.edu
Sitler
Michael R
MR
Kendrick
Zebulon V
ZV