Why You Can Walk Less Than You Used To: Spinal Stenosis and the Shopping Cart Sign

Someone who could walk the seawall for an hour last year now stops after ten minutes because their legs feel heavy and numb. Sitting on a bench for two minutes resets it completely.

Here is why the distance shrinks, why forward lean changes everything, and what the exercise trials actually measured.

What is narrowing, and where

Lumbar spinal stenosis is a narrowing of one or more spaces in the lower spine: the central canal that the spinal cord and nerve roots travel through, the lateral recess at the side of that canal, or the neural foramen where each nerve root exits.

The StatPearls review of spinal stenosis and neurogenic claudication notes that about 90 percent of the population experiences low back pain at some point in life, and that stenosis is most common over the age of 60. The level most often affected is L4 to L5, followed by L5 to S1, then L3 to L4. Among adults over 65 having spinal surgery, lumbar stenosis is the leading pre-operative diagnosis.

One finding shapes how the whole condition should be understood. Most patients over 60 who have stenosis visible on imaging are asymptomatic, which is part of why the exact incidence is hard to determine. A scan showing narrowing does not establish that the narrowing is causing the symptoms. That gap between imaging and experience is a recurring theme in spine care, and we go through it in more detail in our article on when an MRI is needed for low back pain.

Why the distance shrinks

Neurogenic claudication is the pattern that gives the condition away. Symptoms are triggered by walking, standing, or upright exercise, and they are relieved by sitting down or by bending forward at the waist.

The symptoms are usually felt in both legs and tend to involve the whole leg rather than a narrow band. People describe weakness, numbness, and pins and needles. The distance before symptoms start becomes a number people track closely, because it is the thing that decides what they can do in a day.

Most patients have a normal neurological examination, which can be confusing when the symptoms are clearly real. One reliable bedside marker described in the literature is wasting of the extensor digitorum brevis muscle on both feet, a small muscle on the top of the foot.

Because leg symptoms have several possible sources, the assessment works through the alternatives. Nerve-related leg pain from a disc, referred pain from other structures, and circulation problems all need to be separated out, which we cover in our article comparing sciatica from a disc with referred pain.

The forward lean

The characteristic posture for someone with symptomatic stenosis is leaning forward 20 to 40 degrees at the waist. That position increases the space available inside the spinal canal.

This is why a supermarket trip can feel easier than a walk of the same distance. Pushing a cart puts you into exactly that forward lean without any conscious effort.

The same mechanism explains something that surprises most people the first time they hear it: uphill walking is usually better tolerated than downhill walking. Going uphill naturally tips you forward. Going downhill tends to arch the lower back backward, which reduces the space in the canal. On the North Shore that detail is practical, since many local routes involve a long descent that is harder on symptoms than the climb.

Conservative care advice from the clinical literature reflects this directly. Patients are advised to avoid downhill walking and excessive lumbar extension, meaning excessive backward bending of the lower back.

What the exercise evidence shows

A 2023 systematic review published in Clinical Rehabilitation analysed 13 randomised controlled trials with 1,440 participants. The mean age was 65 and 56 percent were female. Between them, the trials covered 23 separate exercise interventions.

Some clear patterns emerged in how those programmes were built. Flexion-based exercise, meaning exercise involving forward bending positions, featured in 17 of the 23 interventions. Supervision was present in 18 of 23. Delivery was land-based in 18 of 23, and physiotherapists delivered 12 of the 23.

Dosage was reasonably consistent. Twenty-one of the 23 interventions ran at least twice a week. Session length was 30 to 60 minutes in 14 of 23. Programmes mostly lasted 3 to 11 weeks, with roughly half running for 6 weeks.

On results, eight interventions produced statistically significant improvements. Cycling stood out for both symptom severity and walking capacity. That fits the mechanism, because sitting on a bike keeps the lower back in a slightly flexed position, the same position that relieves symptoms when standing.

The review also identified a gap. Balance exercises were rarely included across the trials. For an age group where a fall can have serious consequences, that is worth noting when a programme is being designed, and it is the subject of our article on balance work and falls prevention.

How different approaches compare

A 2019 study reported through the NCBI Bookshelf compared three approaches in 259 community-dwelling adults aged 60 and over. The three were medical care delivered by a physiatrist, group exercise classes, and manual therapy combined with individualised exercise.

At two months, manual therapy plus individualised exercise scored better than medical care by 2.1 points and better than group exercise by 2.4 points on the Swiss Spinal Stenosis questionnaire. Both of those differences fell below the clinically important threshold of 3.02 points, so the advantage was measurable rather than large enough to be meaningful to a patient.

Responder rates at two months were 65.3 percent for manual therapy plus exercise, 48.7 percent for medical care, and 46.2 percent for group exercise.

By six months there were no significant differences between the groups, and all groups maintained their walking improvements. The practical reading is that several reasonable approaches help, individualised exercise with hands-on treatment may get there faster, and the walking gains tend to hold once they are made.

What conservative care involves

Physical therapy for stenosis generally combines stretching, strengthening, and aerobic fitness work. Anti-inflammatory medication and epidural steroid injections are also part of the conservative options described in the literature.

In practice a programme is built around what position your spine tolerates. If upright walking runs out at eight minutes, the aerobic work often starts on a bike or on inclines rather than on flat or downhill routes. Strength work targets the hips, legs, and trunk so that the muscles supporting posture do not fade over the same period.

Strength training also matters for bone health in this age group, which we cover in our article on safe strength training with osteoporosis. Progress is usually tracked with a simple measure that means something to you, such as how many minutes you can walk before symptoms start.

When to get it looked at

Book an assessment if your walking distance has been shrinking, if both legs feel heavy or numb after a few minutes upright, or if you find yourself leaning on a cart, a railing, or a counter to get relief.

Some symptoms are an emergency and need immediate attention rather than an appointment. Loss of control of the bladder or bowel, numbness in the area that would touch a saddle, or rapidly worsening weakness in the legs can indicate cauda equina syndrome. Call 911 or go directly to Lions Gate Hospital emergency, the same day, without waiting to see whether it settles.

Also contact your physician promptly for new leg weakness, unexplained weight loss with back pain, fever alongside back pain, or back pain following a fall.

If your walking distance has been getting shorter and nobody has assessed which positions your spine tolerates, book a 30-minute assessment. You can see what we treat or reach the clinic here.

This article is general information, not personal medical advice. A regulated practitioner can confirm whether the patterns described apply to you.

Sources

• Spinal Stenosis and Neurogenic Claudication, StatPearls, NCBI Bookshelf
• Comer C et al., Exercise treatments for lumbar spinal stenosis: A systematic review and intervention component analysis of randomised controlled trials, Clinical Rehabilitation, 2023
• Comparing Three Treatments for Lumbar Spinal Stenosis in Older Adults, PCORI 2019, NCBI Bookshelf
• College of Health and Care Professionals of BC public registry

This article is for general information only and does not constitute medical advice, diagnosis, or treatment. Individual presentations vary, and assessment findings and treatment plans differ from person to person. If you are experiencing severe symptoms, neurological changes (numbness, weakness, bowel or bladder changes), or a significant trauma, contact your physician or emergency services. Care at Medstar Sport Physio & Health is provided by practitioners registered with their respective British Columbia regulatory colleges.