Motor Control
Senior 2 · Physical Education
Motor Control
Lesson 1 of 3
18 min
Watch a football team in the twenty minutes before kick-off at Amahoro Stadium. The players jog, lift their knees, skip sideways and swing their legs. None of it looks like football, yet no serious team leaves it out. A warm muscle contracts faster and more forcefully than a cold one, and a heart that has already sped up can supply that muscle without a sudden shock.
In this lesson you will build a warm-up that fits into a classroom-sized space with no equipment, and you will check that it works by taking your own pulse.
A warm-up is a period of gentle exercise that gets gradually harder and prepares the body for the main activity. A good warm-up has three parts, always in this order:
Long static stretches, which you hold still, are better kept for the cool-down. Holding a stretch for a long time just before exercise can briefly make the muscle weaker.
Jogging in place
High knees
Skipping without a rope
Your heart rate is the number of times your heart beats in one minute, measured in beats per minute (bpm). You can feel it as a pulse in two easy places: on the thumb side of the inside of your wrist (the radial artery), or at the side of your neck beside the windpipe (the carotid artery). Press lightly with your index and middle fingers. Do not use your thumb, because it has a pulse of its own. Count the beats for 15 seconds and multiply by 4.
Worked example
At rest, Keza counts 19 beats in 15 seconds.
Resting heart rate = 19 × 4 = 76 bpm.
After four minutes of jogging in place and high knees, she counts 33 beats in 15 seconds.
Heart rate after the pulse raiser = 33 × 4 = 132 bpm, a rise of 132 − 76 = 56 bpm.
How high is high enough? A common estimate of your maximum heart rate is:
maximum heart rate ≈ 220 − age
Keza is 14, so her estimated maximum is 220 − 14 = 206 bpm. Training is often aimed at 65% to 85% of the maximum: 0.65 × 206 ≈ 134 bpm and 0.85 × 206 ≈ 175 bpm. A warm-up should bring you up towards the bottom of that zone. At 132 bpm, Keza is warm and ready. The formula is only an estimate: real maximum heart rates differ from person to person by 10 to 20 bpm or more.
The talk test. During a pulse raiser you should still be able to speak in full sentences. If you can only gasp single words, you are going too hard for a warm-up.
Tip
Memory hook: Raise, Mobilise, Rehearse. Raise the pulse, mobilise the joints, rehearse the moves. In an exam question that asks you to describe a warm-up, name the three phases in this order and give one example of each.
Work each one out on paper, then check the solution.
Mugisha is 13. Estimate his maximum heart rate and the heart rate at 65% of it.
Solution. Maximum ≈ 220 − 13 = 207 bpm. 65% of 207 = 0.65 × 207 = 134.55, so about 135 bpm.
After jogging, Mugisha counts 24 beats in 15 seconds. What is his heart rate?
Solution. 24 × 4 = 96 bpm. He has not yet reached 135 bpm, so he could continue the pulse raiser a little longer or a little faster.
Put these in the correct warm-up order: leg swings, jogging in place, ankle circles.
Solution. Jogging in place (pulse raiser), then ankle circles (mobility), then leg swings (dynamic stretch).
Why should you take a pulse with two fingers and not your thumb?
Solution. The thumb has its own pulse, so you might count your own heartbeat instead of the one you are measuring.
Before a 100 m race, Uwase's whole warm-up is holding a hamstring stretch for 60 seconds on each leg. Give her two pieces of advice.
Solution. First, she has no pulse raiser, so her heart rate and muscle temperature are still low: she should jog and do high knees first. Second, long static stretches just before a sprint can briefly reduce power: she should use dynamic stretches such as leg swings, then some short strides, and keep static stretching for the cool-down.
Remember
Sources and credits
This lesson adapts CC BY-SA material and is shared under CC BY-SA 4.0.
