HIIT, Flexibility Training and Cross Training

This lesson covers the final three of the nine training methods required by the Edexcel GCSE PE specification (1PE0): High-Intensity Interval Training (HIIT), flexibility training and cross training. Edexcel treats these as three separate methods — they are distinct from the other six methods covered in Lessons 6 and 7. This is an important Edexcel-specific distinction.

---

1. High-Intensity Interval Training (HIIT)

Definition: A training method involving short bursts of maximum or near-maximum intensity exercise followed by brief rest or low-intensity recovery periods.

How HIIT Differs from Interval Training

Edexcel treats HIIT as a separate method from interval training. The key difference is intensity:

Feature	Interval Training	HIIT
Intensity of work	Moderate to high	Very high to maximum (85–100% MHR)
Duration of work	Variable (10 sec to several minutes)	Short (typically 20–45 seconds)
Rest periods	Variable	Short (often equal to or less than work)
Typical session	Flexible structure	Often follows strict protocols (e.g. Tabata)
Energy system	Aerobic and/or anaerobic	Primarily anaerobic

How HIIT Works

A typical HIIT session involves 20–30 minutes of alternating maximum-effort bursts and short recovery periods. The work-to-rest ratio is often 1:1 or 2:1 (e.g. 30 seconds work, 30 seconds rest).

Example HIIT Protocols

Protocol	Work	Rest	Rounds	Total Time
Tabata	20 seconds (maximum effort)	10 seconds rest	8 rounds	4 minutes
30:30	30 seconds (maximum effort)	30 seconds rest	10–15 rounds	10–15 minutes
Sprint HIIT	30 seconds sprint	60 seconds walk	8–10 rounds	12–15 minutes

Advantages and Disadvantages

Advantages	Disadvantages
Time-efficient — significant fitness gains in 20–30 minutes	Extremely demanding — not suitable for beginners
Improves both aerobic and anaerobic fitness	High injury risk due to maximum-intensity effort
Burns a large number of calories in a short time	Requires high motivation to maintain intensity
Continues to burn calories after the session (EPOC)	Can cause nausea or dizziness if pushed too hard
Requires minimal equipment	Requires adequate rest between HIIT sessions (48+ hours)

Sporting Application

Best for sports requiring repeated maximal efforts: team sports (football, rugby, hockey), racquet sports (tennis, badminton), combat sports (boxing, MMA).

---

2. Flexibility Training

Definition: Training designed to improve the range of movement at a joint.

Edexcel treats flexibility training as a separate training method and requires you to know three types of stretching: static, dynamic and PNF.

Types of Flexibility Training

A. Static Stretching

Definition: Stretching a muscle to its furthest point and holding the position for a period of time (usually 15–30 seconds).

There are two forms of static stretching:

Type	Description	Example
Active static	The performer stretches the muscle themselves using their own body	Reaching forward to touch toes and holding
Passive static	A partner or apparatus assists the stretch, pushing the limb further	A partner gently pushing the performer's leg further into a hamstring stretch

When to use: During the cool-down phase (or as a separate flexibility session). Static stretching before exercise may temporarily reduce power and speed, so it is generally not recommended immediately before high-intensity activity.

B. Dynamic Stretching

Definition: Stretching involving controlled, sport-specific movements that take the muscle through its full range of movement repeatedly — not holding the stretch.

Feature	Detail
Movement	Active and controlled (not bouncing)
Hold time	None — continuous movement
Examples	Leg swings, arm circles, walking lunges, high knees

When to use: During the warm-up phase. Dynamic stretching prepares muscles for activity by increasing blood flow, temperature and range of movement.

C. PNF Stretching (Proprioceptive Neuromuscular Facilitation)

Definition: An advanced stretching technique that involves a cycle of stretching, contracting (isometric hold) and further stretching to achieve a greater range of movement.

How PNF works (typical method):

1. The muscle is passively stretched to its limit (by a partner).
2. The performer contracts the stretched muscle isometrically (pushes against the partner) for 6–10 seconds.
3. The performer relaxes, and the partner pushes the limb into a deeper stretch (beyond the original limit).
4. The new position is held for 15–30 seconds.

graph LR
    A["Passive stretch<br>to limit"] --> B["Isometric contraction<br>(push against partner)<br>6-10 seconds"]
    B --> C["Relax"]
    C --> D["Deeper stretch<br>(partner pushes further)<br>Hold 15-30 seconds"]

    style A fill:#3498db,color:#fff
    style B fill:#e74c3c,color:#fff
    style C fill:#f39c12,color:#fff
    style D fill:#27ae60,color:#fff