Hi Alyson!
Great question! The strength of recommendations in this CPG can be strong, moderate, weak, theoretical, best practice, or research. You can see all of them summarized on Table 2 (page 54) in the CPG article: https://journals.lww.com/jnpt/Fulltext/2020/01000/Clinical_Practice_Guideline_to_Improve_Locomotor.8.aspx (let me know if you need me to email you a copy!)
Strong evidence has a high level of certainty of moderate to substantial benefit, harm or cost, or a moderate level of certainty for substantial benefit, harm, or cost based on a preponderance of level 1 or 2 evidence. It is associated with the language “should” and “should not”.
So, there can be strong evidence (or moderate or weak) in support of or NOT in support of each intervention.
Similarly, “weak evidence” does not mean negative effects of an intervention or poor outcomes. It refers to our level of certainty. “Strong evidence” means we have a pretty high level of certainty that a specific outcome will occur – whether it be a positive or negative outcome. Weak evidence means we have a lower level of certainty of the outcome.
For the specific interventions you mentioned, there is strong evidence that they do not improve walking speed or distance in the population studied (ambulatory patients who are at least six months out from CVA, TBI, or iSCI). Keep this narrow scope of specific outcomes and patients in mind as you are analyzing the recommendations. The authors are not saying that these “should not” interventions are bad – just that they are ineffective for improving walking speed and distance in patients with chronic CVA/TBI/iSCI who can walk without manual assistance. If we were looking at other metrics – say balance confidence or falls risk – balance training would likely be recommended. If we were looking at a different patient population – say non-ambulatory individuals – the recommendations for treadmill training and robotics may be different.
Hope this helps!
Chrissy