The Student Notes for This Experiment Are on Page 49

From strength to strength Lesson 1 Does the size of muscles affect performance in different activities? The student notes for this experiment are on page 49. Aim Students investigate whether there is a relationship between muscle size and sports performance. Equipment From the kit box From your school ● tape measures ● stopclocks ● 1 l bottles of sand optional: ● multi-gym, dumbbells ● sturdy box at about knee height

Safety ● Identify students with asthma so they can have their inhaler close at hand and use it if required. ● Ensure students are dressed appropriately for the activities – for classroom-based activities, normal school uniform with sensible shoes will be fine. Trainers are required for some of the aerobic activities. ● Identify any student (such as those with heart/lung problems) not able to take part in school PE/games lessons. They may need to be excused from taking part in the physical part of this activity but can take on a time-keeper or data recording role. ● If PE activities and equipment e.g. multi-gym, weights are used, it is essential to use the expertise, advice, and supervision of trained PE staff. ● Healthy competition is encouraged but be aware of and discourage excessive competition between students as it can lead to over-exertion and possible fainting or injury. ● Ensure students carry out the activities in a suitable place, clear of any obstruction. Running the experiment 1 Students work in same-sex pairs. Students could carry out the work in a group of three. 2 Students take it in turns to measure the size of their upper arm in millimetres with a tape measure. They measure around the upper arm at the largest point when the biceps are contracted; the arm should be bent at 90 degrees. Then they take a second measurement of the upper arm at the same point when the arm is hanging at the side of the body and the biceps are relaxed. Students must ensure that the tape measure is level all the way round the arm and that it does not squeeze the skin. 3 One student in the pair takes part in different activities (as many as time allows) but must complete some warm-up exercises and stretches first. Suggested warm-up exercises are walking on the spot and then raising it up to a gentle jog on the spot, followed by stretches for the quadriceps, hamstrings, and calves (see page 57). The other student counts the number of repetitions of each activity in 2 minutes. See the Student sheet for the protocol for obtaining evidence. 4 They record results and then swap roles. Ages Under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 UK:England And Wales License you can copy, share and adapt the materials as much as you like, as long as it is not for commercial use. Where material is owned by a third party, certain restrictions may apply that you have to comply with. In particular, where a copyright line is included on 14–16 a photograph you must not modify, adapt or remove that photo from its context.

Suggestions for classroom-based activities

Activity Equipment Bicep curls Bottles of sand Triceps dips Sturdy box at about knee height, or chair seat

bicep curls

triceps dips

Suggested classroom-based activities: bicep curls and triceps dips.

Suggestions for activities using sport facilities

Activity Equipment Chest presses Dumbbells Triceps extensions Dumbbells or fixed weights Pull-ups Pull-up bar

Ages 14–16

chest presses

triceps extensions pull ups

Suggested activities using sports facilities: chest presses, triceps extensions, pull-ups.

5 There is an opportunity to have a class discussion on whether there is a relationship between muscle size and number of repetitions performed in the selected activities. During any discussion, height and maturation status of students will need to be taken into account.

Expected results It would be expected that students with larger biceps would be able to perform more repetitions of the activities in 2 minutes compared to students with smaller-sized arm muscles. This is because larger muscles are able to produce more force and therefore will not tire as easily as smaller muscles. Some students may have larger biceps due to excess body fat rather than large muscles size and therefore they may not perform as well as expected in the activities.

Next lessons In Lesson 2 you will be running a carousel of three experiments (B–D), on upper and lower body strength, power and endurance and fatigue, with two stations for each experiment. Lesson 3 will give students the opportunity to analyse and evaluate all the data they have collected. This is also when they will be able to upload the data from Experiment B into the ‘Live Data Zone’ section of the In the Zone website (www.getinthezone.org.uk) and analyse and interrogate national data from UK schools.

Ages 14–16