Motor control: jogging, jumping jacks, arm circles and high knees

1Why this matters

Watch a Primary 1 pupil try a jumping jack: the arms go up just as the legs close, the feet slap the ground, and after five jumps the rhythm falls apart. Now watch a Senior 3 student: arms and legs open and close together, the landings are quiet, and the rhythm lasts a whole minute. Their muscles are not so different. What has changed is motor control, meaning how well the brain and nerves direct the muscles.

Every skill you will learn in PE this year, from the cartwheel to the volleyball pass, is built from simple movements like these. In this lesson you will learn four whole-body exercises well enough to do them correctly and to lead a group through them.

2What motor control is

Motor control is the way the nervous system (the brain, the spinal cord and the nerves) plans and regulates movement. Every movement runs as a loop:

1. The brain chooses a movement and sends signals along the nerves to the muscles.
2. The muscles contract in a set order and with a set force.
3. The senses report back: the eyes, the balance organs in the inner ear, and sensors in the muscles and joints that tell you where each arm and leg is.
4. The brain uses this feedback to correct the next movement.

Each time you practise, the loop becomes smoother. Sports scientists describe three stages in learning a skill:

• Cognitive stage: you must think about every part of the movement, and mistakes are frequent.
• Associative stage: you practise, and the mistakes become fewer and smaller.
• Autonomous stage: the movement is automatic, so your attention is free for the game around you.

Whatever you repeat is what becomes automatic. That is why you learn a movement slowly and correctly before you try it fast.

3Four whole-body exercises, step by step

1. Jogging on the spot, then short runs

1. Stand tall with your eyes forward and your shoulders relaxed and low.
2. Land lightly on the balls of your feet, underneath your hips.
3. Bend your elbows to about 90° and swing your arms forwards and backwards, each arm moving with the opposite leg.
4. After 30 seconds, jog forward 20 m and back with the same posture.

2. Jumping jacks (also called star jumps)

1. Start with your feet together and your arms by your sides.
2. Jump and land with your feet a little wider than your shoulders, while your straight arms swing out and up above your head.
3. Jump again, bringing your feet together and your arms back down to your sides.
4. Arms and legs open together and close together. Land on the balls of your feet with soft knees.

Low-impact version for anyone with sore knees or who cannot jump: step one foot out to the side as your arms rise, step it back as they fall, and alternate sides.

3. Arm circles

1. Stand with your feet shoulder-width apart and your arms straight out to the sides at shoulder height.
2. Make 10 small circles forwards, letting them grow gradually bigger.
3. Repeat 10 circles backwards. Keep your shoulders down, away from your ears, and your trunk still.

Arm circles move the shoulder joint through its range, which prepares it for throwing, serving and handstands.

4. High knees

1. Start by jogging on the spot, then lift each knee to hip height.
2. Stay tall: do not lean back to lift the knee higher.
3. Pump the opposite arm with each knee, and keep your foot contacts quick and quiet.

Worked example: leading the group

This unit asks you to carry out exercise routines and guide others through them. Kalisa's teacher asks him to lead his class through the four exercises: 40 seconds for each exercise, and 20 seconds before each one to explain and demonstrate it.

Step 1: plan the time. Exercise time = 4 × 40 = 160 seconds. He explains 4 times: 4 × 20 = 80 seconds. Total = 160 + 80 = 240 seconds = 4 minutes.

Step 2: place the group. He arranges the class in three lines facing him, an arm's length apart in every direction. He stands so that the sun is behind the class and nobody has to squint to see him.

Step 3: show, then start. "Jumping jacks. Watch me first." He demonstrates two slowly, facing the class. Then: "Ready... begin!" He counts aloud in fours to keep everyone in rhythm.

Step 4: watch and correct. He notices that Mutesi's arms go up as her feet close. He gives one short cue, "Out together, in together", and praises her when she gets it right.

A good leader demonstrates, explains in a few words, keeps everyone safe and able to see, and corrects one thing at a time.

Practice

Answer each one on paper, then check the solution.

Solution. It is the way the brain, spinal cord and nerves plan and regulate movement, using feedback from the senses to correct each movement.

Solution. He should land on the balls of his feet with soft, slightly bent knees. Bent knees absorb the landing force, which protects the ankles, knees and back, and makes the landing quiet.

Solution. Exercise time = 5 × 30 = 150 s. There are 4 changeovers between 5 exercises: 4 × 15 = 60 s. Total = 150 + 60 = 210 s = 3 minutes 30 seconds.

Solution. The cognitive stage: she is still thinking about every part, and mistakes are frequent.

Solution. Whatever you repeat becomes automatic. If you practise a fault many times, the fault becomes automatic too, and it is hard to change later.