Why you should add walking on an incline to your exercise routine
As a low impact activity that involves large muscle groups, walking already has a lot going for it. But it's when you add an incline that it starts to get really interesting.
Compared to walking on the level, additional muscle actions are required to raise your centre of mass when you walk uphill. Researchers at the University of Colorado investigating the effects of slope and speed on leg muscle activations found that incline walking makes your hip, knee, and ankle extensor muscles work a lot harder. In the healthy young adults they tested, walking up a 9° slope (that's a 15.8% incline) as opposed to on the level increased, for example, glute activation by 345% and hamstring activation by an impressive 635%.
As well as enhancing lower-limb muscle strength, there's more good news about uphill walking in this month's issue of the journal Gait & Posture.
A knee that is perfectly aligned has its load-bearing axis on a line that runs down the middle of the leg, through the hip, knee and ankle. Unfortunately, as many as 4 in 10 of us have what's known as varus (bow-legged) alignments2 - such misalignment is associated with developing knee osteoarthritis, particularly if someone is overweight.
Haggerty and colleagues quantified the influence of incline walking on knee joint mechanics. They found that while flexion and extension movements increased, potentially damaging frontal plane (that's sideways) movements of the knee were significantly reduced at higher gradients. This reduction could have positive effects on knee joint health such as potentially reducing cartilage degeneration of the knee joint, reducing pain, and decreasing the rate of development of osteoarthritis. As a result, the authors recommend treadmill gradients of 10% to 15%, or even greater, for both rehabilitation and exercise protocols.
If you imagine incline walking is too slow to promote cardiovascular health, you need to give it a go! Try this 30-minute session out (if need be, you can adjust the difficulty up or down according to your fitness requirements).
0-5 minutes - 2% incline at 6.5kph.
5-9 minutes - 10% incline at 6.0kph.
9-10 minutes - 12% incline at 5.5kph.
10-11 minutes - 15% incline at 5.0kph.
11-15 minutes - 10% incline at 6.0kph.
15-16 minutes - 12% incline at 5.5kph.
16-17 minutes - 15% incline at 5.0kph.
17-21 minutes - 10% incline at 6.0kph.
21-22 minutes - 12% incline at 5.5kph.
22-23 minutes - 15% incline at 5.0kph.
23-27 minutes - 10% incline at 6.0kph.
27-30 minutes - 2% incline at 6.5kph.
Holding on is cheating and will diminish the benefits. So slow down the pace if you find yourself clinging on to the treadmill. Equally, it may be a while before you feel comfortable tackling the steepest gradients. But note, it's at inclines of 10% and above that the benefits really start to kick in. So, if you can, aim for at least that even if you have to go more slowly to do so.
For some reason the metabolic response in women is greater (perhaps because they have more body mass in their buttocks and thighs). But whatever your gender, acceleration of calorie consumption and burning of fat tissue are additional health benefits incline walking has to offer.
Whether you're recovering from injury or want to add some variation to your workout routine, hopefully you'll now feel inclined to give uphill walking a go.
1. Franz JR, Kram R. The effects of grade and speed on leg muscle activations during walking. Gait Posture 2012; 35; 143-7.
2. Haggerty M et al. The influence of incline walking on joint mechanics. Gait Posture 2014; 39; 1017-21.
3. Brouwer GM et al. Association between valgus and varus alignment and the development and progression of radiographic osteoarthritis of the knee. Art Rheum 2007; 56: 1204-11.
4. Kang J et al. Physiological and biomechanical analysis of treadmill walking up various gradients in men and women. Eur J Appl Physiol 2002; 86: 503-8.