This Physical Activity intervention arm is a 6-month excercise protocol for SCI people, delivered 3 times per week, comprising of 2 supervised group-based exercise sessions & one home-based (unsupervised) one.

The exercise programme is a progressive evidence-based tailored exercise regime comprising aerobic, resistance and balance exercises, applied at a moderate intensity (60-80% of targeted heart rate).

The exercise programme is a 6-month progressive tailored-based exercise regime comprising

• aerobic exercises (40-60%)
• resistance exercises (20-40%)
• balance with resistance exercises (20%) .

This is peformed 3 times weekly, it is tailored to each individual but delivered in a small group-based manner. Two sessions are supervised by physiotherapist /exercise scientist and one session is unsupervised, home-based.

The Greek version of the Mini-BESTest (Mini-Balance Evaluation Systems Test) is used to assess the balance of each participant comprising four primary assessment balance categories (anticipatory, reactive postural control, sensory orientation, dynamic gait). The Mini-BESTest focuses primarily on dynamic balance and contains 14 different balancing tasks, each scored from 0 (lowest level of function) to 2 (highest level of function). Thus, overall scores range from 0 (lowest level of function) to 28 (highest level of function) and subsequent subscales are scored as: Anticipatory tasts (0-6), Reactive Postural Control (0-6), Sensory Orientation (0-6) & Dynamic Gait (0-10). Mini-BESTest takes about 10-15 minutes to be administered.

The Hand Grip Strength test is an objective, established and standardised measure of upper limb muscle strength, comprising a standard electronic hand dynamometer (Jamar) for measuring muscle strength of the hand (measured in kgs).

The lower limbs strength is measured using the 30 seconds Sit-to-Stand test, which is an objective, established and standardised measure of lower limb muscle strength. Participants are seated in the front part of a standard chair with their hands crossed in front of their chest, and they are asked to stand up completely (full extension of their knees) and sit back down to the chair as many times as possible during 30 seconds (measuring the repetitions).

The 2 Minute Walk Test is an established and objective test for measuring aerobic capacity. Participants are placed in a hallway of nine meters and are asked to cover as much ground as they can in two minutes (measured in meters).

The Greek version of the Falls Self-efficacy International Scale (FES-I_GREEK) is used to evaluate Fear of Falling. FES-I is a 16-item questionnaire with scores ranging from 16 to 64 points. Higher scores indicate higher fear and concern regarding falls.