SIMONE REISMAN, LEE D. WALSH, and UWE PROSKE Department of Physiology, Monash University, Melbourne, Victoria, AUSTRALIA
ABSTRACT REISMAN, S., L. D. WALSH, and U. PROSKE. Warm-up Stretches Reduce Sensations of Stiffness and Soreness after Eccentric Exercise. Med. Sci. Sports Exerc., Vol. 37, No. 6, pp.929-936,2005. Purpose: A commonly used method for warm-up before exercise is to stretch muscles. How this benefits performance remains uncertain. After a period of eccentric exercise, there is muscle damage accompanied by an increase in passive tension, perceived as a sensation of increased stiffness in the exercised muscles. We have tested the idea that warm-up stretches might reduce levels ofpassive tension to reduce sensations of stiffness and soreness after eccentric exercise. Methods: Subjects eccentrically exercised elbow flexors of one arm on an isokinetic dynamometer. The other arm acted as a control. After the exercise, measurements were made of resting elbow angle, as an indication of passive tension levels, before and after one or five large, passive arm extensions. Additionalmeasurements made at 24 h included soreness levels in response to muscle stretch or vibration. Results: After the exercise, the relaxed elbow adopted a more flexed posture than normal, an effect that slowly subsided over the next 4 d. Five rapid arm extensions returned arm posture back to near control levels. The flexed posture then gradually redeveloped over the next hour. At 24 h postexercise,extending the arm produced some soreness as did muscle vibration. The pain from arm extension and vibration was reduced after a series of arm extensions. Conclusions: The flexed posture at the elbow is due to an increase in passive tension in elbow flexors as a result of muscle damage from the eccentric exercise. Stretch reduces passive tension. Benefits from the lower tension are reduced sensations ofstiffness and soreness. This represents a new proposal for the mechanism for passive stretches as a warm-up strategy. Key Words: PASSIVE TENSION. WARM-UP, MUSCLE DAMAGE, PAIN, VIBRATION. COMPRESSION
fore they actually carry out the exercise. Taken \4 literally, the idea is to prepare muscles for the period of activity by raising their temperature. But the term is often used more loosely tomean any kind of preparation that will bring the muscles into a state of peak performance. Many accounts have been written on this subject (1,2). However, there does not seem to be any emerging consensus about underlying mechanisms. A variety of passive and active procedures have been included under the heading of warm-up; however, we want to restrict discussion to one particular technique. It is acommon experience to see football players and track and field athletes preparing for their competitive events by passively stretching their muscles (17). We have asked the question "what might be the physiological basis for carrying out such warm-up stretches?"
Address for correspondence: Uwe Proske, Department of Physiology, Monash University, Victoria 3800, Australia; E-mail: email@example.com. Submitted for publication May 2004. Accepted for publication February 2005. 0195-9131/05/3706-0929/0 MEDICINE & SCIENCE IN SPORTS & EXERCISE, Copyright C 2005 by the American College of Sports Medicine DOI: 10.1249/01.mss.0000170471.98084.70
ost exercising individuals practice a warm-up be-
In this study, we have considered one specific mechanism. Following a period ofeccentric exercise in someone unaccustomed to it, there is evidence of muscle damage (for a review, see Proske and Morgan (13)). One of the indicators of the presence of damaged muscle fibers is an increase in whole-muscle passive tension (5,25). This is tension generated without stimulation, so is unaccompanied by any EMG (8). When the damage is in elbow flexor muscles, the increase in passive...