Warm up is done routinely before any exercise regimen or sport activity. Let’s find out what happens in our body when we do a warm up and how it enhances performance.
Why do warm up ?
Increases muscle temperature
Temperature of the muscles is generally lower than our core body temperature. Warming up increases the muscle temperature. This prepares the muscles in our body for optimal performance.
Hemoglobin in the blood carries and delivers oxygen to the muscle. Increased temperature helps oxygen to detatch from hemoglobin.
Increases blood flow
When muscles are warmed up there is increased blood flow resulting in more oxygen and nutrients delivery to the muscles.
Glucose and fatty acids are the major fuel for muscle cells. In the presence of oxygen, glucose and fatty acids are oxidised and ATP molecules ( energy currency of the cells ) are released .These molecules provide energy for all the cellular events.
Due to the continuous supply of oxygen , more energy molecules are produced in the cell for the subsequent workout.
Decreases muscle viscosity
When something is highly viscous, it means it is not pliable. A good warm up decreases the viscosity of the muscle resulting in smoother contractions.
Improves neuromuscular coordination
All the muscles are controlled by signals coming from the brain.Warm up ensures effective communication between the brain and the muscle.
Increases nerve receptor sensitivity
Warm up also increases skin temperature. This increases the sensitivity of free nerve endings and nerve receptors in the skin . These receptors carry information to the brain for better coordination and execution of movements.
Increases nerve transmission speed
Warm up increases muscle contraction speed and decreases reaction time. This is important to avoid falls and twists.
Increases flexibility
Warm up increases the flexibility of the muscles. It increases the length of the muscle and range of motion of the joints. This protects the muscles from injuries.
How intense should be the warm up?
At the end of warm up, under normal conditions, there should be very mild sweating and no fatigue should be felt. The individual should feel geared up for the following sporting event or exercise.
For how long should one warm up?
Warm-ups are generally done for 5 to 15 minutes before the main exercise or sports. And longer warm up deplete energy stores and decrease heat storage capacity. This results in impaired performance. Also, warm up is done within the aerobic threshold.
Passive methods
Passive warming methods increase temperature by external means. These are generally pre- warm up for conditioning the mind and the body.
Passive warming increases the core temperature without depleting the energy reserve of the muscles. Additionally, it may give adequate time for mental preparation and gathering focus.
Warm bath
Hot shower or immersion bath with water of ~47⁰ C for 10 minutes improves performance. The heat dilates the blood vessels due to which oxygen and nutrient supply increase. It also eliminates metabolic wastes accumulated in the muscle.
Sauna
Sauna is a closed, heated chamber which mostly uses dry heat to increase the body temperature. In general, sauna increases cardiac output, left ventricular function, and increases blood flow through the body. It removes metabolic waste and decreases inflammatory markers in the circulation.
According to a study conducted in 2015, exposure to 75-82⁰ C temperature for 15 minutes improves blood flow, increases pain tolerance by releasing endogenous opioids like endorphins and dynorphins.
The muscles release a protein called heat shock protein, which decreases muscle viscosity and makes the connective tissue more pliable. In the event of muscle injury in the forthcoming sport event or exercise, this facilitates faster muscle recovery.
Active methods
The muscle temperature declines rapidly after passive warmup. Active methods involve actively moving the muscles. The metabolic changes are higher and long lasting.
General warm up
This involves non specific body movements. The movement may include one group of muscles / joints at a time (eg. arm and wrist ) or involve the whole body and all major joints ( squats, burpees, jumping jacks, jogging, skipping rope)
Specific warm up
Warming up specific body parts used in the subsequent sport or exercise. This warm up conditions the required neural pathways for better neuromuscular coordination.
Eg. Jogging as warm up before running, swings for golfers etc
Stretching
Static vs Dynamic stretching
Static stretches involves stretching and holding a single or group of muscles for a period of time (15 to 60seconds). The muscles, fascia, ligaments and tendons gradually lengthen. Passive stretching increases flexibility and strength but may not improve blood flow to the muscles adequately to increase the temperature.
Studies suggest doing dynamic stretching before active exercise or sports. Dynamic stretching involves moving a part of the body towards full range of motion and repeating the movement several times.
Controlled, active stretching of the muscle occurs.This increases the muscle and core temperature, activates stretch receptors and prepares the body better for explosive moments.
Sun salutations for warm up
Sun salutations involves series of sequential postures with synchronised breathing. It can be a dynamic stretching exercise as the muscles contract actively while holding a posture and during transition from one posture to another.
When the sequence is done in a moderate pace, (holding only 2 to 3 seconds between each posture) it becomes an aerobic exercise. The heart rate can raise up to 70% of your maximum heart rate.
Since it involves all major muscles (trunk muscles,upper and lower extremity muscles) and joints (wrist,shoulder,hip, knee and ankles) it swiftly increases the temperature. Also, the focus on breathing improves oxygen uptake.
Jumping rope
Jumping rope is an exercise which involves multiple groups of major muscles with synchronised arm and leg movements. It rapidly elevates the core temperature and muscle temperature. Not only that, there is more activation of the nervous system due to its rhythmic movement , coordinated eye movements and kinesthetic feedback from holding the rope.When done in a moderate speed, it can be a great head to toe warm up.
Take home
As a routine, warm up should include aerobic exercises, dynamic stretching and activity specific exercises. When done in this sequence, it increases the heart rate and circulation, increases core and muscle temperature and finally improves neuromuscular coordination.
Finally, warm up should be just adequate to energize and gather momentum and not be so intensive , depleting the energy levels.
References
- Stretching anatomy Arnold G. Nelson, Jouko Kokkonen
- Mueller-Wohlfahrt HW, Ueblacker P, Haensel L, editors. Muscle Injuries in Sports. New York: Thieme Medical Publishers, Incorporated; 2013.