The Most Important Part of a Workout

Warm up exercises are crucial to any sport or fitness program and should precede every exercise session. This component of the work out is the most important part and, if done correctly, will reduce risk of injury and improve overall movement quality. A proactive approach should be used in the warm up to improve strength, mobility and flexibility in areas where the athlete is weak. There are major factors influencing the extent of improvement elicited from a warm-up, such as structure and specificity of warm-up to the task.

Warm-ups are beneficial for many reasons. First, it serves to prepare the athlete mentally and physically for exercise or competition. Second, a thorough warm up will result in physiologic responses to improve subsequent performance. Temperature-related responses will increase muscle tissue temperature, enhance neural function, and disrupt transient connective tissue bonds. Non-temperature-related effects are related to a rise in heart rate and respiratory rate and lead to increased blood flow to muscle, elevation of baseline oxygen consumption, and post-activation potentiation. Post-activation potentiation is the phenomenon by which the contractile history of a muscle directly affects its subsequent ability to generate force in a rapid manner. In other words, post-activationpotentiation results in short-term improvement in performance (i.e. jumping) due to use of a conditioning exercise before hand (i.e. back squats).

Among these positive effects of a warm up are faster muscle contraction and relaxation of both agonist and antagonist muscles, improvements in the rate of force development and reaction time, increases in muscle strength and power, lowered viscous resistance in muscle and joints, enhanced metabolic reactions, and increased psychological preparedness for performance. Furthermore, increased muscle tissue temperature has been shown to increase resistance to tears.

There are several key elements to a proper warm up. The warm up should progress gradually and provide sufficient intensity to increase muscle and core temperatures without causing fatigue or reducing energy stores. Warm-ups should last 10-20 min and end no more than 15 minutes before the start of the next activity, as positive effects of warm-up start to dissipate after this time.

There are two main phases of a proper warm up. The first phase, the general warm-up, should consist of five minutes of slow aerobic activity, such as jogging, skipping, cycling, rowing, or jump rope. The goal of the general warm up phase is to increase key physiological parameters—heart rate and respiratory rate—to improve blood flow to muscles, increase deep muscle temperature and decrease viscosity of joint fluids. The second phase, the specific warm up, incorporates movements similar to those to be performed in the upcoming sport or exercise with a goal of activating key muscle groups. This phase is analogous to stretching with addition of movement patterns required for the workout and in the athlete’s overall development by actively moving through the range of motion. For example, a person warming up for squats with a barbell may perform body weight lunges and squats in the specific warm up phase. The athlete will perform specific movements in this phase that progress in intensity until they are performing at the intensity required for the subsequent competition or training session. This phase presents the opportunity to address particular movement issues the athlete demonstrates and also work on other aspects of performance such as speed and agility.

Beneficial warm up effects are best elicited with active movements rather than passive. Dynamic stretching in a warm up is time efficient and will target activation of key muscle groups, maintain the increased temperature of the general warm up phase and incorporate many joints. Examples of dynamic stretching are toy soldiers for the hamstrings and low back muscles, spiderman lunges for the hips, and inchworms for the pectoral muscles and triceps. Static stretching prior to exercise has shown negative effects on performance in force production, power development, running speed, reaction time, and strength endurance. However, studies have shown that static stretching performed after exercise compared to pre-exercise facilitates greater range of motion improvements. The elevated body temperature post-exercise increases the elastic properties of collagen within muscles and tendons, which allows for a greater stretch magnitude.

The range of motion required for the exercise should be considered in a warm up. Those in sports that require greater range of motion, such as golf, volleyball or gymnastics, may need to spend more time with dynamic stretching than those with a lower range of motion required for exercise.

The more power necessary for the sport or activity, the more important the warm-up becomes. A warm up routine for plyometrics, such as box jumps, broad jumps and sprinting, deserves its own discussion. In short, a warm up for plyometric exercises should consist of low-intensity, dynamic movements. For example, butt kicks and straight-leg jogging prepare the body for the impact of plyometrics and emphasize quick take off and landing to mimic plyometric activities.

Article written by Dr. Jessica Khani, PT, DPT, CSCS


The information provided is not medical advice and is not intended to be used in place of seeking advice from a professional.



Fletcher, I.M., and B. Jones. The effect of different warm-up stretch protocols on 20 meter sprint performance in trained rugby union players. J Strength Cond Res 18(4):885-888. 2004.

Knudson, D.V., P. Magnusson, and M. McHugh. Current issues in flexibility fitness. Pres Council Phys Fitness Sports 3:1-6. 2000.

Funk, D.C., A.M. Swank, B.M. Mikla, T.A. Fagan, and B.K. Farr. Impact of prior exercise on hamstring flexibility: A comparison of proprioceptive neuromuscular facilitation and static stretching. J Strength Cond Res 17(3):489-492. 2003.

Haff, Greg. Triplett, Travis. Essentials of Strength and Conditioning. Fourth edition. Champaign, IL: Human Kinetics, 2016. Print.