Transcription:

Scott Webb: Though most of us take walking for granted, folks who have suffered a stroke or a spinal cord injury often need to learn to walk again. And joining me today to discuss the benefits of high-intensity gait training and helping people to learn to walk again is Sandy Lim. She's a physical therapist at Franciscan Health.

This is the Franciscan Health Doc pod. I'm Scott Webb. Sandy, it's so great to have your time today. We're going to talk about folks that need to learn to walk again after a stroke or a spinal cord injury. And for our purposes today, we're talking about high-intensity gait training. And as I just mentioned, I don't know a lot about this, so it's great to have your expertise. Let's start here, what is high-intensity gait training?

Sandy Lim: High-intensity gait training is basically walking and stepping practice that is vigorous enough to keep your heart rate over a certain target or within a certain range. Each range or each level or target range is specific to every patient. And it's determined by the physical therapist using the resting heart rate and/or their age to calculate their max heart rate or their heart rate reserve. The physical therapist will then assign walking activities or exercises that will keep your heart rate within the target range.

Scott Webb: Okay. That makes sense. So we're going to compare and contrast that with traditional gait training in a bit. But maybe this sounds like sort of a basic question, but I think it's important to answer, what is walking?

Sandy Lim: Yeah. So walking in its most basic form is our bodies kind of just fall forward and our leg actually just comes out and catches us. It alternates from leg to leg, obviously. And it becomes just this alternating rhythm of trunk and legs moving back and forth. Typically, there are eight phases that each leg has to move through to take each step. And each phase has certain movements or muscle actions that occur and we call those gait kinematics.

Scott Webb: That's interesting, because as you say, for most of us, it's this sort of involuntary thing, right? The legs and the torso and everything just kind of does what it's supposed to do, but eight phases, that's really interesting. So let's talk about the difference between high-intensity gait training and traditional gait training.

Sandy Lim: So with traditional gait training, we usually focus on correcting those gait kinematics or correcting for normal walking pattern. The physical therapist would typically provide cues or guidance to achieve a normal walking pattern. So the physical therapist may say something like, "Make sure you land on your heel" or "Make sure you kick your leg out," things like that. High-intensity gait training, however it uses the concept of conservation of energy to normalize walking patterns.

So a normal walking pattern is actually the most energy efficient type of walking pattern there is. If you think about the way like a toddler learns how to walk, when they first learned how to walk, it looks nothing like a normal walking. It's this very high steppage walk. And then that's why after about five, ten feet, they squat and they rest because they've worn themselves out. So over time, the brain kind of figures out, "Hey, this is way too much energy," and it figures out how much energy it actually needs to expend and babies develop into this normal walking pattern that we see most people walk with.

So that is the same with high-intensity gait training. Having a patient walk at high intensities to reach fatigue forces the brain to find a way save energy while walking. The brain goes, "There must be a better way. We're getting too tired," and then it leads to a more normal walking pattern and it saves energy.

Scott Webb: Wow. That is so cool. And I was picturing in my head both of my kids when they were learning to walk and, you're right, like they can only go a short distance before they would get pooped out and you can kind of understand as you're explaining it here how this all works. So who's a good candidate or when would it be appropriate for someone to seek out or for you to work with somebody on high-intensity gait traning?

Sandy Lim: Any patient that's pretty much had a stroke or brain injury or an incomplete motor spinal cord injury that were ambulatory before being hospitalized. There's actually a lot of research now for factors for stroke and spinal cord injuries to determine if high-intensity gait training would be best for them. The physical therapist can help determine which factors and if high-intensity gait training would be appropriate for an individual. Things like age and the severity of their paralysis, cognition, sensation, even sitting balance can all play a role in determining who would have the best outcomes for walking after a stroke or brain injury or spinal cord injury.

Scott Webb: Are there some folks where this would just not be appropriate for them?

Sandy Lim: Women who are pregnant. It probably wouldn't be best for them at this point in time. Anyone with a leg fracture or any kind of weight bearing status, it would also not be appropriate for them because, in some cases, they can't put weight on their legs. Amputees would also not be appropriate for this. High-intensity gait training would also not be appropriate for anyone with a significant cardiovascular history. So for example, if they were in the hospital for having a heart attack and then let's say, two days later, they have a stroke, they would not be someone who would be appropriate yet for such an intense regimen of therapy.

Scott Webb: Yeah, and it does sound fairly intense. I'm wondering, does it only really improve walking or are there some other benefits as well?

Sandy Lim: It improves walking as well as walking-related concepts like walking speed and quality and symmetry. But because walking is a higher form of movement, it also naturally improves things like balance, sit to stand, any kind of transfers and bed mobility, simply because walking is more difficult to do than, say, getting out of bed or standing up from a chair.

Scott Webb: Yeah, it definitely is. And maybe you can tell us from a patient's perspective, what does this actually feel like?

Sandy Lim: During the session, the physical therapist will watch over the patient's heart rate and their response to exercise to make sure they're responding correctly and to keep them safe. Some patients may notice they are breathing a little harder or they're sweating which are normal responses to exercise and usually indicates that they're working hard. Patients may get tired as well during the exercise. They may also feel like it's a little difficult to do, because it is forcing their brain to move a little bit faster and think a little bit faster. So that may also come into play.

Scott Webb: Yeah. You can see there may be some mental and physical challenges along the way. Are there some additional challenges as well when we think about the sessions?

Sandy Lim: Yeah. We kind of want to reflect real life. We want to be able to prepare the patient to return home. So we got to consider all the things we wouldn't normally do on a daily basis. So typically, we would do things in addition to walking. So a lot of times we walk and carry our groceries. We walk and carry our lunch. We increase our walking speed to cross streets or catch the elevator. We walk outside in the grass and in gravel, so they are uneven and we have to be prepared for those kinds of surfaces. We walk and talk. Nowadays, a lot of us walk and text, though I don't recommend we do that.

Scott Webb: We sure do.

Sandy Lim: Yes, a lot of us do that. We definitely walk and read signs all the time to figure out where we're going to look both ways when we're crossing streets. All those things require good balance and being able to not think about walking. And so that's what we try to do, is encourage walking to become almost like a subconscious level, like we would normally do.

And then there's a lot of variability in some of the tasks we do in general. So by changing these activities up in our sessions, it encourages learning. There's a lot of research that has shown that varying tasks actually improve learning and can help long-term retention of walking.

Scott Webb: Yeah, I see what you mean. And just thinking about that, right? It's not just the walking. It's balance it's doing these different tasks, the different types of walking, different surfaces and so on. So when we think about the high intensity part of this, how high do folks' heart rates get?

Sandy Lim: Typically, we try to keep it within 75% to 85% of their heart rate max or heart rate reserve. It does depend on age. The younger the person is, the higher their range typically is. So for someone who's maybe 55, their heart rate max would be somewhere around 170. So their range would probably be about 125 to about 145 respectively. And then for example, for someone who's 75 years old, their heart rate max would be 155. And their range would be 115 to about 130.

Of course, we make additional adjustments for each patient. So if that 75-year-old is also on say like beta blockers or calcium channel blockers, which can affect how the heart works, we would adjust their range down. So their range that we would work in would be about 105 to about 120. And then we can also use things like the rate of perceived exertion scale, which is how the patient feels, how hard they're feeling like they're working. So if we ask them how hard do they feel like they're working, they can give us a number on that scale to indicate can we push them a little harder or do we need to ease it off. It just varies from patient to patient.

Scott Webb: Yeah, I see what you mean that it's not just the numbers that you're monitoring, but it's also asking the patient, "How do you feel? How much are you exerting yourselves? Are you comfortable in this range?" Obviously, the goal to be able to push them a little bit as well. And I'm sure folks listening would want to know what kinds of equipment you use to monitor the heart rate or any other equipment you might use during a session.

Sandy Lim: So we use a lot of pulse oxes just to measure their oxygen and heart rate. Sometimes we'll put a heart monitor on them, which is a strap that goes around their chest and that usually just measures heart rate. Blood pressure is also measured throughout the session. As for equipment that we use during the session, one of our favorites is body weight support systems. There's various kinds out there. They can be attached to the ceiling or they can be free-standing and it's just a device that they wear a harness in that helps hold them up if it needs to be or it's used for safety, depending on patient's need. Sometimes the body weight support system can also be used with or without a treadmill. But treadmills are great for increasing heart rates and to really getting in the vigorous exercise and the amount of stepping that we would like to get patients to do. We'll take them out and do stairs. Sometimes we'll add ankle weights to these things while they're walking around, sometimes weighted vests, any kind of objects for stepping over or around. So kind of whatever item we can find that we can use, we'll use it.

Scott Webb: Yeah. Maybe creating a little bit of an obstacle course kind of thing to simulate real world situations in which we all find ourselves in and, as you've mentioned, a lot of us just take for granted. But when you're relearning to walk after an event, stroke or otherwise, you can really see the value in working with a physical therapist. So really awesome. Are there any adverse effects from high-intensity gait training?

Sandy Lim: Currently, there's no research indicating there's any increased risk for high-intensity gait training or aerobic training beyond just the standard types of practice as well as beyond less intense interventions. By keeping the heart rate less than 85% of a heart age-predicted heart rate, that helps mitigate the risks. For some patients, if needed, physical therapists can also get clearance from the appropriate medical doctors to do high-intensity gait with certain patients.

Scott Webb: Well, this has been really educational. As I prefaced when we got started here, I didn't know a lot about high-intensity gait training, listeners may not as well, so great to have your expertise. So much good information today. Thanks so much and you stay well.

Sandy Lim: All right. Thank you very much.

Scott Webb: For more information about stroke rehabilitation, visit franciscanhealth.org and search stroke rehab.

And if you found this podcast helpful, please share it on your social channels and be sure to check out the full podcast library for additional topics of interest. This is the Franciscan Health Doc Pod. I'm Scott Webb. Stay well, and we'll talk again next time.