PART 1: RATIONALE, EVIDENCE AND KEY PRINCIPLES SUPPORTING MOTOR TRAINING IN THE SCI-MT TRIAL.
The Motor Training provided during the SCI-MT Trial is directed at increasing motor function at and below the injury. This will be measured using the Total Motor Score of the International Standards for the Neurological Classification of SCI. For example, in a person with partial paralysis of the lower limbs, the Motor Training (i.e., task-specific training and strength training) will be used to improve the ability to stand or walk as well as to increase lower limb muscle strength. Of course, Motor Training as typically provided in rehabilitation can also be targeted above the injury. For example, it can be used to improve the ability of a person with paraplegia to transfer through their neurologically intact upper limbs. However, this is not the focus of the SCI-MT Trial. Rather, the focus is on improving motor function at and below the injury with the primary aim of increasing total motor scores.
The Motor Training provided during the SCI-MT Trial is also directed at helping people regain the ability to move in a way that is as close as possible to that of a non-disabled person. For example, gait training will be directed at walking without aids and orthoses if possible. Similarly, upper limb training will focus on regaining the ability to reach and grasp with the kinematics and kinetics of a non-disabled person where possible. Needless to say, even small amounts of residual weakness may ultimately require some type of adaptation or compensation that alters the kinematics and kinetics of movement from that of a non-disabled person. The extent of adaptation or compensation will depend on the extent of neurological loss and may range from a slight variation to the need for extensive orthoses, aids, manual guidance, or assistance.
The SCI-MT Trial intervention will be provided in a high dosage. Dosage is determined by a combination of exercise intensity, duration, and frequency. Participants in the SCI-MT Trial will be required to exercise as hard as possible (i.e., at high intensities and with a high number of movement repetitions) for 12 hours per week over 10 weeks (i.e., for a long duration and at a high frequency). There are no stipulations about the number of sessions per week but typically the 12 hours are provided over 5 to 10 sessions of 1 to 2 hours duration each. .
The two components of Motor Training are described below.
1. Task-specific training
Task-specific training has its origins in the motor relearning approach which was widely advocated in rehabilitation by Carr and Shepherd in the 1980s [2, 3]. Behavioural and neurosciences have moulded its development over the years. Animal and human studies indicate that task-specific training is a strong stimulus for neuroplasticity both at the site of injury and throughout the neural pathways responsible for purposeful movement [4–6]. Task-specific training involves practice of movements that are specific to the desired functional outcome. The key principles of task-specific training are as follows.
Repetitions
Task-specific training requires repetitious practice of purposeful movements. The evidence for repetitious practice is compelling, particularly in the stroke literature [7–9]. Hundreds or even thousands of daily steps and upper limb movements are required to improve walking ability and arm function respectively after a stroke or SCI [7, 10, 11]. Nonetheless, patients undergoing rehabilitation in SCI units get very little repetitious practice [12]. This is primarily because patients do not spend the amount of time in therapy that is required for repetitious practice in addition to the many other types of interventions that they need during rehabilitation. The SCI-MT Trial aims to increase the amount of repetitious practice by adding an extra 12 hours of therapy per week for 10 weeks.
Active (not passive)
Task-specific training involves active voluntary muscle contractions, specific to a functional task, with the aim of learning and improving the ability to perform that task. Movement practiced in this way involves cognitive processing which is believed to drive neuroplasticity. This is supported by animal [13] and human [14, 15] studies. Passive movements that are solely driven by the help of therapists, robotics, electrical stimulation, or other devices do not typically involve active muscle contractions and are unlikely to lead to such changes [16, 17]. However, assistive technologies are often used in conjunction with the effort of the patient to provide a form of task-specific training. For example, locomotor training with or without body weight support (BWS) on a treadmill can be used to augment patients’ attempts at walking [18, 19]. Similarly, upper or lower limb functional training using robotics has some features in common with task-specific training [17, 20, 21]. Activity Based Therapy (ABT) is another example. Although a clear definition of ABT is currently lacking [22], it typically focuses on high volumes of walking practice using various combinations of robotics and electrical stimulation [23–25]. A key underlying principle of the SCI-MT intervention is that only active exercises will be practiced during task-specific training although attempts at movement can be assisted by robotics, electrical stimulation, or any equipment available at the training sites and as deemed appropriate by the trial therapists.
Progression
Task-specific training needs to be progressed [26, 27]. This includes progressing the difficulty of part-task and whole-task practice. Walking on a treadmill is an example of whole-task practice. As the ability to walk improves, the difficulty of the training needs to be increased, with the practice expanded to different environments with increasing task complexity resulting in increased cognitive or physical demands [27]. Part-task practice focuses on repetition of components of the desired task, with a biomechanical analysis underpinning the choice of the specific components to be practiced [28]. Part-task practice of walking may include exercises such as stepping forwards, weight shifting in standing, or even a much simpler practice of knee and hip extension on a sliding tilt table (see www.physiotherapyexercises.com for over 1,500 exercises which include whole-task and part-task practice). Like whole-task practice, part-task practice also needs to be progressed and relies on reassembling the components back to the whole-task once the person is ready to do so [8]. The ongoing progression of task-specific practice is required to the point where the ability to perform the task becomes an automatic skill [29].
The progression of task-specific training is critical to the SCI-MT Trial and can be done in many ways. Examples of progression include increasing the number of repetitions, changing the environmental set-up to increase the challenge, or manipulating the difficulty of the task. Physiotherapists typically select new or additional exercises every few days or weeks and constantly modify existing exercises to ensure the training is challenging and progressed. Exercise selection is highly reliant on the therapists’ ongoing analysis of patients’ attempts at movement, as well as therapists’ decision making and clinical expertise. Appropriate progression is also reliant on careful and detailed recording of what a person does today in order to ensure they do more tomorrow. For this reason, Practice Sheets will be used for all training sessions in the SCI-MT Trial (see Fig. 1 for an example), where features of the exercise reflecting the intensity, set-up, and amount of practice will be recorded. For example, if a person repeatedly practices sit to stand, the following details may be recorded to direct the future progression: the height of the chair, the number of repetitions of sit to stand, the position of the feet in relation to the base of the chair, the amount of weight put through each foot, the time taken to complete a set number of repetitions, or some subjective measure of exertion such as the Borg Scale of perceived exertion.
Another important aspect of the SCI-MT Trial intervention is target orientated instructions. This helps ensure training is progressed. So, prior to commencement of any exercise the therapist and participant will together reflect on what was done in the previous session and set a new exercise target for the current session. For example, if a person could do 40 repetitions of sit to stand from a set height yesterday then perhaps today’s target will be to complete 44 repetitions from the same height. Alternatively, if a person can slide his or her thumb 40mm along a ruler whilst working towards the goal of getting the hand around a cup, perhaps next time the aim will be to slide the thumb to 42mms (see Fig. 2). The setting of targets for every exercise makes it very clear to participants what they are trying to achieve. It provides motivation and it enables the therapist and participant to see improvement even if very small. It also ensures that training is progressed. However, it requires meticulous measuring and recording on Practice Sheets: an important aspect of the SCI-MT Trial.
Feedback
Appropriate and timely feedback is integral to skill acquisition [30]. Feedback provides the person with important information about their attempts at movement. It is critical for helping the person change future attempts at movement and is central to optimal motor learning. Feedback provided by therapists is known as augmented feedback. Augmented feedback is particularly important for people with SCI because of their sensory-motor impairments. Augmented feedback can be provided in the form of knowledge of results (KR) and knowledge of performance (KP) [26, 27]. Knowledge of results refers to information about the outcomes of attempts at movement. Examples of KR feedback include information about the accuracy of stepping onto a target, the speed of walking or the number of sit-to-stand exercises completed. In contrast, KP refers to information about the quality of movement, or the kinetics and kinematics. Examples of KP include feedback about how well a person straightens his or her knee when standing or what a person does not do when trying to shift weight from one leg to another. Evidence suggests that both KR and KP are important for optimising motor learning during task-specific training [31–33]. Both types of feedback need to be provided at an appropriate time and in an appropriate amount of detail that matches the person’s stage of learning. So too much feedback can be just as detrimental to learning as too little feedback. Similarly, feedback provided at the wrong time can hinder attempts at movement. Therefore, an important aspect of the Motor Training provided as part of the SCI-MT Trial will be well-timed and appropriate KR and KP feedback. The use of Practice Sheets in which the therapists and participants set and review exercise targets and goals will encourage the provision of KR feedback.
Goal driven
Task-specific training must be meaningful to the person. That is, it must be based on his or her own goals [34]. Setting meaningful goals can increase a person’s satisfaction with the intervention and improve motivation to engage in therapy. It can also ensure that the training is specific [35]. Motor Training based on goals that are specific and difficult is likely to produce better outcomes than training without a goal or with a non-specific easily attained goal [27]. The SMART acronym is often used to facilitate the goal-setting process, prompting therapists to set goals with patients that are Specific, Measurable, Attainable, Realistic and Timebound (there are several variations of the words associated with each letter) [36, 37].
Task-specific training as part of the SCI-MT Trial will be based on goals set by participants in collaboration with the therapists. Two ten-week and two six-month goals will be set during the baseline assessments that form part of the formal assessment schedule of the trial. These will be set using the SMART principles of goal setting. The goals will be related to participants’ activity limitations and participation restrictions and be amenable to SCI-MT intervention. Then, each week during the SCI-MT training, the therapist and participant will together identify up to four smaller goals just for the week. These weekly goals will be reviewed and progressed and will underpin the choice of task-specific exercises included in the Motor Training program.
2. Strength Training
Strength training is the second component of Motor Training. Whilst it is an important aspect of SCI-MT Trial, strength training is considered supplementary, with the priority being given to task-specific training.
There is strong evidence about the effectiveness of strength training in muscles with grade 3 or more strength [38, 39]. This evidence points to the importance of progressive resistance training involving high loads and low repetitions. This typically involves 2–4 sets of 6–12 repetition maximum muscle contractions, performed two-three times per week, over eight weeks with progression as muscles increase in strength [38, 39]. The most effective way to strengthen very weak muscles (grade 1 and 2) is less clear although progressive resistance training is not a viable option because it is very difficult to operationalise (high load and low repetitions). By necessity therefore, therapists tend to administer strength training for very weak muscles in the form of low loads and high repetitions. This type of training usually involves repeated contractions of the very weak muscle through the available joint range of motion to the point of muscle fatigue. Progress is achieved by changing the position of the limb and manipulating the effects of gravity and surface friction until the person can train against gravity, and then against resistance. The evidence about the effectiveness of this form of strength training for the very weak is inconclusive [40] but included as part of the SCI-MT intervention because it is widely administered and may be effective when combined with task-specific training.
Of course, the distinction between strength training and task-specific training for the very weak can become blurred once the focus of an exercise involves high numbers of repetitious contractions. For example, knee and hip extension exercises completed on a sliding tilt table can be considered a form of strength training but can also be a form of part-task training aimed towards improving the ability to perform sit-to-stand. For the purpose of this trial, the distinction between the two is based on whether the repetitious practice involves complex movements in the context of purposeful activity or simpler exercises targeting strength training of a specific muscle group.
The key features of the strength training provided as part of the Motor Training of the SCI-MT Trial are:
Progression
The strength training for muscles of grade 3 and 4 strength will follow the principles of progressive resistance training (high load and low repetitions), whilst the strength training for muscles of grade 1 and 2 strength will follow the principles of low load and high repetitions training. Both types of strength training will be progressed, and the participants will be encouraged to work to fatigue in every session with the difficulty of exercises increased as required. For very weak muscles, strength training will be transitioned to higher loads with lower repetitions, as well to task-specific training, as soon as possible.
Goal driven with feedback
Like task-specific training, strength training needs to be meaningful to the person and based on goals that are set at the beginning of each week. In addition, setting clear targets for each exercise, so that the participants know exactly what they are trying to achieve is an important aspect of strength training. The participants will be provided with KR feedback (e.g., information about the numbers of repetitions and amount of load completed with each exercise) to optimise the effectiveness of the training.
Part 2: Operationalising And Standardising The Motor Training Provided As Part Of The Sci-mt Trial
Whilst Motor Training will be individualised to the needs of each participant, it is important that the intervention is standardised within the SCI-MT Trial as far as possible, with trial therapists adhering to the key training principles. This is being achieved by articulating the key principles and guidelines of the SCI-MT in a 3-hour online training package (delivered via Zoom) to all trial therapists. The training is compulsory and is provided to every SCI-MT site. The key principles of SCI-MT Trial are summarised in Table 2.
Table 2
A summary of the key principles of SCI-MT intervention
| General SCI-MT principles | Task-specific training | Strength training |
| For muscles with Grade 1 and 2 strength | For muscle with Grade 3 and 4 strength |
| • Twelve hours of weekly therapy will be delivered in one-to-one sessions in the therapy gym for 10 weeks. • The number and duration of sessions per week is not stipulated but typically the 12 hours per week will be provided over 5 to 10 sessions of 1 to 2 hours duration each. • Therapy will target the Total Motor Score, secondary outcomes, and the participants’ goals • Practice Sheets will be used for every session • Exercise targets will be set for each exercise during each therapy session • Therapy will be progressed as much as possible. • Participants will be challenged to work as hard as possible in every session. • Each session will be spent with the participant actively engaged in exercise. • The participants will be re-assessed regularly throughout the 10 weeks. | • Focus on high numbers of repetitions • Include part-task or whole-task practice • Provide manual assistance only if essential • Feedback will be used to provide knowledge of performance and knowledge of results • Clear instructions and demonstrations will be provided • Treadmills or robotics will be used to complement training when and if appropriate | • The focus will be on high repetitions and low load • Effects of gravity and surface friction will be manipulated to enable active muscle contraction • Resistance/load will be increased as soon as possible • The strength training will be done within the context of a functional activity if possible • Manual assistance will only be provided if essential | • Training will follow the principles of progressive resistance training (ie., 3 x 10-12RM) • The strength training will be done within the context of a functional activity if possible |
In addition, an Intervention Manual is provided to all trial therapists alongside the training package (see Appendix 1 for a copy of the intervention manual). The Intervention Manual details the training principles of the SCI-MT Trial as well as information about the use of Practice Sheets, the type of equipment that can be used, and the staff who can deliver the 12 hours of Motor Training per week. Examples of Motor Training exercises are presented in the Intervention Manual and are categorised into common activities that can be targeted by Motor Training. The manual also includes completed Practice Sheets using four different hypothetical case studies. These demonstrate ways in which exercise set-up, intensity of training, and time spent on each exercise across a week can be documented.
The SCI-MT intervention will be delivered by a healthcare professional (e.g., Physiotherapist, Occupational Therapist, Exercise Physiologist) appropriately qualified to deliver all or some aspects of Motor Training once they have completed the compulsory training. The 12 hours per week of Motor Training will be provided to the intervention participants on a one-to-one basis by the therapists in a therapy gym. The time allocated to Motor Training will be dedicated to as much active exercise as possible, although it will also include rest, set-up, and chat. Management of fatigue will include rests as required, with encouragement to resume exercise as soon as possible. Mental practice [41] can be used as an adjunct to training if a participant gets excessively fatigued.
The use of Practice Sheets will be at the core of delivering the SCI-MT intervention. Therapists and participants will refer to the Practice Sheets together at the beginning of each week to review previously set goals and negotiate 2–4 new goals. Therapists will also use Practice Sheets to set exercise targets, and to document exercise intensity, set-up, and duration within each session. Dosage parameters documented in the Practice Sheets will be reviewed during each session, and this will be used to encourage the participants to work as hard as they can, and to progress the exercises from day to day, and week to week.
The exercise dosage delivered during the 12 hours of weekly SCI-MT Trial intervention will be documented as the amount of time dedicated to active practice during each therapy session. Time alone will not capture all aspects of intensity or dosage, but it will be used in the SCI-MT Trial as a crude measure of intensity that is practical to capture. This is consistent with other studies in stroke and SCI rehabilitation [42–44]. Amount of time spent on motor training during every SCI-MT session will be documented in Case Report Forms (CRF). Furthermore, time spent on each individual exercise (in addition to other training parameters reflecting intensity of training) will be recorded in the Practice Sheets, which together with the CRFs, will reflect the intensity of the SCI-MT training program.
Importantly, there will be ongoing auditing of the intervention by three trial clinical experts to ensure that the intervention is being delivered as intended. The audits will involve regular reviews of the Practice Sheets at each site, with provision of feedback and ongoing training of the trial therapists as required. In addition, the fidelity of the intervention will be examined in detail with a process evaluation that will run alongside the trial.