Supply teacher deck · PE · Year 9

Evaluating Wearable Fitness Tracker Data and Privacy

Worksheet Stimulus Worked example
Slide 1 of 7
05:00

Slide 1 of 7 · Settling starter · PE · Year 9

5 minutes

Evaluating Wearable Fitness Tracker Data and Privacy

Nia, a Year 9 sprinter, wears a wrist fitness tracker during training and shares her runs on a social fitness app. Today you will test how accurate her wrist tracker really is and check whether her app settings put her privacy or well-being at risk.

While the register is called: write your name, class and date on your worksheet, then look at Table 1 on the stimulus sheet.

Starter question: In Session 1 (100 m sprints), the chest-strap benchmark recorded 184 bpm, while the wrist tracker recorded 172 bpm. What is the difference in bpm?

DCF: Citizenship → Health and well-being · LNF: Interpreting data Pen, paper and calculator · no computers needed

Slide 2 of 7 · Today’s brief and key formulae · PE · Year 9

5 minutes

Key formulae and concepts for today

Wrist trackers use an optical sensor on the skin and GPS satellites. You will compare them against a chest-strap heart-rate monitor and a measured athletics track.

Heart-rate error & recovery rate

  • Absolute error (bpm) = Chest-strap HR − Wrist tracker HR
  • Recovery rate (bpm/min) = (Peak HR − 2-min recovery HR) ÷ 2

Percentage inaccuracy & privacy

  • Percentage inaccuracy (%) = (Error ÷ True measured distance) × 100
  • Geolocation privacy: GPS maps can reveal where a pupil lives and when they run alone.
DCF: Citizenship → Health and well-being · LNF: Interpreting data Keep the stimulus sheet beside your worksheet

Slide 3 of 7 · Step 1 · PE · Year 9

10 minutes

Step 1: Heart-rate error and recovery rate per minute

Use Table 1 on the stimulus sheet to complete the 6 training sessions on your worksheet. Then calculate the mean error across all 6 sessions, and compare sprint sessions with steady runs.

SessionChest-strap peak (bpm)Wrist tracker peak (bpm)Error (bpm)2-min recovery HR (bpm)Recovery rate (bpm/min)
1 (100 m sprints)18417212136(184 − 136) ÷ 2 = 24

Compare: Work out the mean error for the 4 high-intensity sprint sessions (Sessions 1, 2, 4 and 6) versus the 2 steady sessions (Sessions 3 and 5).

Step 1 on your worksheet · 10 minutes Show your division for each mean

Slide 4 of 7 · Step 2 · PE · Year 9

10 minutes

Step 2: Percentage inaccuracy on GPS sprint distances

Use Table 2 on the stimulus sheet to calculate the distance error and percentage inaccuracy for each run, and test whether the wrist GPS can replace a stopwatch on sprint days.

Formula: Percentage inaccuracy = (Distance error ÷ True track distance) × 100

Worked first row (100 m sprint): Error = 100 − 92 = 8 m · Percentage inaccuracy = (8 ÷ 100) × 100 = 8%.

Check Section 2(b): why does a GPS watch that records position every 3 seconds struggle on a 200 m bend?

Step 2 on your worksheet · 10 minutes Use Table 2 on the stimulus sheet

Slide 5 of 7 · Step 3 · PE · Year 9

12 minutes

Step 3: Audit privacy and well-being risks in the app

Inspect Section 3 of the stimulus sheet showing Nia’s PulseBand Go profile and notification settings. Identify the risk of each setting and write a safer replacement setting.

Privacy & safeguarding

  • Public profile shows full name, age (14), school and photo.
  • GPS map starts and ends at her home address at 07:15 every Tuesday and Thursday.
  • Live beacon broadcasts her real-time location.

Physical & mental well-being

  • 21:30 “Streak lost!” alerts push her to exercise late at night even with a sore ankle.
  • Public leaderboards increase anxiety and risk of overtraining.
Step 3 on your worksheet · 12 minutes Complete all 4 rows of the privacy and well-being audit

Slide 6 of 7 · Step 4 · PE · Year 9

5 minutes

Step 4: Write recommendations for the PE department

Write a structured recommendation (4 to 5 sentences) advising the PE department on when wrist trackers are useful, when other equipment is needed, and what privacy rules pupils must follow.

Include in your recommendation:

  • Accuracy evidence: quote the mean heart-rate error on sprints (12.5 bpm) versus steady runs (2 bpm), and GPS inaccuracy on sprints (6% to 9%) versus steady runs (1%).
  • Equipment choice: use wrist trackers for steady endurance runs, but stopwatches, measuring tapes and chest straps for short sprints.
  • Safeguarding rule: private profiles, no live location, and hidden home/school start-finish zones.
Step 4 on your worksheet · 5 minutes Back every point with a figure from Steps 1 and 2

Slide 7 of 7 · Plenary review · PE · Year 9

3 minutes

Quick self-check before handing in

Check your figures against the board before your worksheet is collected.

  • Mean heart-rate error: 9 bpm across all 6 sessions (12.5 bpm on sprint sessions vs 2 bpm on steady runs).
  • Recovery rates (bpm/min): S1 = 24, S2 = 25, S3 = 22, S4 = 26, S5 = 20, S6 = 26.
  • GPS percentage inaccuracy: 100 m = 8%, 200 m = 9%, 400 m = 6%, 2,000 m = 1%.
  • Privacy & well-being: Private account, home/school GPS privacy zone enabled, live beacon off, streak notifications disabled.
Ensure your name, class and date are on your worksheet Leave the stimulus sheet and calculator on your desk