Physical Activity Definitions

Physical activity is an umbrella term that refers to any type of bodily movement, produced by skeletal muscles, that results in energy expenditure (Caspersen et al. 1985). This umbrella term includes all types of physical activity; these can be broadly categorized as leisure, transport, household, education, and occupational activities. Within the context of spinal cord injury, most of the research and clinical focus has been on physical activities that people perform in their leisure time, particularly exercise and sport.

Exercise is a subcategory of physical activity that is defined as “planned, structured, and repetitive bodily movement done to improve or maintain one or more components of physical fitness” (Caspersen et al. 1985). Physical fitness refers to a set of attributes that relate to one’s ability to perform physical activities and includes muscular strength and endurance, cardiorespiratory fitness, body composition, and flexibility. Simply stated, exercise is a physical activity that people typically do with a plan in mind, and that they perform on a repeated basis to improve some aspect of their physicality.

Sports are also typically planned and structured activities that may be performed to achieve improvements in fitness. But unlike exercise, sports have a competitive element. This element provides the definitional distinction between sport and exercise activities.

Other types of physical activity, such as transportation activity (e.g., walking or handcycling to school), household activity (e.g., vacuuming the floor), or occupational activity (e.g., lifting and carrying boxes at work) might also improve physical fitness. However, for the most part, these types of physical activities are not widely performed by people with SCI at a duration or intensity that would be expected to confer fitness or health benefits (Perrier et al. 2017).  There is also some uncertainty as to whether occupational and household physical activities confer the same fitness and health benefits as leisure-time physical activities (Holtermann & Stamatakis 2019).  For these reasons, the focus of most of the research literature, and this chapter, is on leisure-time physical activities.

Here are definitions of terms used within this chapter:

• Aerobic activities: physical activities that are done continuously and that increase the participant’s heart and breathing rate (e.g., wheeling, swimming, hand cycling, dancing).
• Exercise: “planned, structured, and repetitive bodily movement done to improve or maintain one or more components of physical fitness” (Caspersen et al. 1985).
• Flexibility: an aspect of physical fitness that refers to the range of motion at a joint (Caspersen et al. 1985).
• Leisure time physical activity: Physical activity that people choose to do during their free time. The types of activities that are done in leisure time likely vary across cultures, but would typically include exercise, sports, and active play (including with children or pets). Here are examples of leisure-time physical activities reported by people with SCI in a large Canadian sample (Martin Ginis, Latimer et al. 2010):
  • Wheeling (i.e., self-propelling one’s own wheelchair)
  • Arm/Hand cycling
  • Resistance training
  • Walking
  • Playing sports such as wheelchair basketball, wheelchair rugby, sledge hockey, wheelchair tennis, bocce, and wheelchair curling
  • Gardening
  • Woodworking
  • Taking the dog for a walk
  • Playing with children
  • General fitness activities such as yoga, aerobic fitness classes, and tai chi
  • Fishing
  • Standing
  • Swimming
• Neuromotor: pertaining to, or affecting the effects of neurons on muscles. In other words, activities that may affect balance, coordination, agility, gait, and proprioception (Bushman 2012).
• Physical inactivity: An insufficient physical activity level to meet present physical activity recommendations (Tremblay et al. 2017).
• Rehabilitative exercise: These are exercises performed to restore function or movement and are typically performed in a rehabilitation setting (e.g., physiotherapy clinic). While similar to ‘exercise,’ these activities may not necessarily improve physical fitness. For instance, rehabilitative exercises such as practicing wrist flexion and extension may help improve hand function, but will not necessarily lead to increases in strength or endurance.
• Resistance exercise or Muscle-strengthening activities or Strength training activities: “movement using body weight or external resistance that improves muscular strength, power, or endurance, and may ultimately positively impact mobility, function, and independence” (Chan et al. in press).

Sedentary behaviour: any waking behavior characterized by an energy expenditure ≤1.5 metabolic equivalents (METs), while in a sitting, reclining, or lying posture. For people who use a manual wheelchair or a power chair: Use of electronic devices (e.g., television, computer, tablet, phone) while sitting, reclining or lying; reading/writing/drawing/ painting/talking while sitting; sitting in a bus, car or train; moving from place to place in a power chair; being pushed while passively sitting in a manual wheelchair (Tremblay et al. 2017).