Reflex Inhibition of Electrically Induced Muscle Cramps in Hypohydrated Humans

MILLER, KEVIN C.1; MACK, GARY W.2; KNIGHT, KENNETH L.2; HOPKINS, J. TY2; DRAPER, DAVID O.2; FIELDS, PAUL J.3; HUNTER, IAIN2

Medicine & Science in Sports & Exercise:
doi: 10.1249/MSS.0b013e3181c0647e
Basic Sciences
Abstract

Introduction: Anecdotal evidence suggests that ingesting small volumes of pickle juice relieves muscle cramps within 35 s of ingestion. No experimental evidence exists supporting the ingestion of pickle juice as a treatment for skeletal muscle cramps.

Methods: On two different days (1 wk apart), muscle cramps were induced in the flexor hallucis brevis (FHB) of hypohydrated male subjects (∼3% body weight loss and plasma osmolality ∼295 mOsm·kg−1 H2O) via percutaneous tibial nerve stimulation. Thirty minutes later, a second FHB muscle cramp was induced and was followed immediately by the ingestion of 1 mL·kg−1 body weight of deionized water or pickle juice (73.9 ± 2.8 mL).

Results: Cramp duration and FHB EMG activity during the cramp were quantified, as well as the change in plasma constituents. Cramp duration (water = 151.9 ± 12.9 s and pickle juice = 153.2 ± 23.7 s) and FHB EMG activity (water = 60% ± 6% and pickle juice = 68% ± 9% of maximum voluntary isometric contraction EMG activity) were similar during the initial cramp induction without fluid ingestion (P > 0.05). During FHB muscle cramp induction combined with fluid ingestion, FHB EMG activity was again similar (water = 55% ± 9% and pickle juice = 66% ± 9% of maximum voluntary isometric contraction EMG activity, P > 0.05). However, cramp duration was 49.1 ± 14.6 s shorter after pickle juice ingestion than water (84.6 ± 18.5 vs 133.7 ± 15.9 s, respectively, P < 0.05). The ingestion of water or pickle juice had little impact on plasma composition 5 min after ingestion.

Conclusions: Pickle juice, and not deionized water, inhibits electrically induced muscle cramps in hypohydrated humans. This effect could not be explained by rapid restoration of body fluids or electrolytes. We suspect that the rapid inhibition of the electrically induced cramps reflects a neurally mediated reflex that originates in the oropharyngeal region and acts to inhibit the firing of alpha motor neurons of the cramping muscle.

Author Information

1Department of Health, Nutrition, and Exercise Sciences, North Dakota State University, Fargo, ND; 2Department of Exercise Sciences, Brigham Young University, Provo, UT; and 3Department of Statistics, Brigham Young University, Provo, UT

Address for correspondence: Kevin C. Miller, Ph.D., ATC, CSCS, North Dakota State University, Health, Nutrition, and Exercise Sciences, NDSU Dept #2620, PO Box 6050, Fargo, ND 58108-6050; E-mail: Kevin.C.Miller@ndsu.edu.

Submitted for publication July 2009.

Accepted for publication September 2009.

©2010The American College of Sports Medicine