Barefoot, forefoot, zero rise, shape-up. Shoe technology is packed with more gimmickry and marketing hype now than any time in history. It’s hard to cut through the chatter to something meaningful. It’s even harder to find a gem when it is cryptically concealed behind the jargon of codified model names and features.
Karhu started in 1916 by making track and field equipment that went on to include shoes. The company has engineered great shoes, perhaps some of the very best in each category. The problem with Karhu is sifting through the technology that makes the shoes so great.
Karhu’s “Move Forward” philosophy is intended to produce less vertical movement of the runner using their patent-protected Fulcrum design. The idea is less vertical movement, more forward movement- and less road shock. That’s the Karhu marketing shtick. The reality is the shoes feel naturally soft and stable, with a “balanced” sensation I haven’t felt from any other shoe design with medial “plugs” to control ride and stability.
I test a lot of shoes, most of them entirely adequate for their purpose. But I wouldn’t train in all of them on a day-to-day basis. Those I do keep, with very few exceptions, wind up being modified with insoles to tune the ride. When I got my first Karhus a year ago I ran in them without an aftermarket insole. It was an epiphany: This shoe doesn’t need a $40 insole to tune the ride. It’s already tuned.
Karhu uses a midsole construction technique designed to reduce how much you bounce up and down while running. Less bouncing up and down, or “vertical oscillation”, less shock from your feet hitting the ground. When Karhu came to clinic us on their shoes it was an endless PowerPoint presentation with charts and graphs that show force vectors, acceleration and G loads. Frankly, it was lost on me. They gave us some shoes; I put them on the pile… I didn’t run in them until months later. I wished I hadn’t waited.
The Karhu Benefit for Triathletes:
I run in the evening after work, generally after commuting to and from work on a bike. My commute is about 20-25 minutes on the bike, and I usually ride it hard. Getting off the bike after commuting is great brick training since I am running off the bike nearly every day of the week. When I ran in Karhus I discovered something interesting: These shoes run better off the bike than anything I’ve tried except maybe Zoot’s transition-specific shoe geometry. In some ways the Karhus may be better off the bike over longer distances since they seem to have a softer, more shock mitigating ride than most Zoots. I think what I’ve found is the perfect 70.3 and 140.6 shoe, and a great shoe for the high frequency runner who does a lot of workouts, especially on tired legs.
I haven’t done an Ironman in Karhus. Yet. But one thing occurred to me while watching the endless PowerPoint slides on reducing vertical oscillation: Late in the run at Ironman your legs hurt. Every time your foot hits the ground it feels like it is doing so with the force of a sledge hammer. The pain seems to reverberate upward through your body. If a shoe reduced the up and down movement of the runner while improving shock absorption, maybe it wouldn’t hurt so badly. I wasn’t willing to ride 112 miles and run on tired legs to test my theory, so I did the next best thing. I took 10 days off running.
“This shoe doesn’t need a $40 insole to tune the ride. It’s already tuned.”
Coming back from a lay off means when I run I am going to be sore. Even with fresh shoes and good insoles I’m sore during the first few runs coming back after time off. On the 11th day of my running hiatus I put on a pair of Karhus and went 5.9 miles, settling in to a 7:30 pace after doing nothing for 10 days. I tried not to think about how bad my legs would hurt and how much aspirin I’d be swallowing over the next two days.
The shoes run with a distinctly different ride than conventional shoes. The heel feels softer- but it does not feel lower. This is not a low drop shoe. I measured the heel at 34 millimeters and the forefoot at 18 millimeters for a drop of about 16 mm. You come into the ground softly on this shoe, owing to a lot of cushion in the medial heel, where a lot of people tend to begin their foot contact with the ground during the gait cycle. Faster runners may land slightly farther forward moderating this soft sensation. The fulcrum design in each category of Karhu shoes is different depending on the application. The Fast 2 Fulcrum Ride has a more forward fulcrum and a firmer fulcrum than the Stable ride shoes. Fast 2 Fulcrum Ride would be my choice for a long run on tired legs at a 70.3 or 140.6 event.
Does the reduction in vertical movement idea work? My vote: Absolutely. So much so, that it feels a bit odd at first – you sort of skim a long- running low and soft. It takes some getting used to. When we put another test runner in the shoes, a better runner than I, he tended to “bound” upwards to try to defeat the shoe. It took a few minutes for him to settle into the geometry of the shoe and run “lower”. If you think about it, this is exactly how you tend to run off the bike at Ironman, your knees barely coming up as you try to resist descending into the “Ironman Shuffle”. Whether you’re running a 10K or a marathon after 112 miles on the bike running with less vertical movement takes less energy and is less painful.
“Does the reduction in vertical movement idea work? My vote: Absolutely.”
How did my legs feel the day after running following my 10-day layoff experiment? Well, my muscles were still a little tender, but less so than after any other period off the run. The big difference was reduction in joint pain. After three knee surgeries and even with a lot of glucosamine/chondroitin my knees are still a junk yard. Joint pain after returning to running from a lay off is normal for me. I had no joint pain after my first run in the Karhu Fast 2 Fulcrum Ride.
The Karhu Fast 2 Fulcrum Ride is 10 ounces exactly in a Men’s size 9 according to our scale, not a lightweight, but a reasonable weight for a luxury ride and the vertical mitigation features.
Fit on this shoe is generous, perhaps because of a lack of hard outer heel counter or toe box. The upper is delightfully unstructured, with a demi-heel counter molded into the back and a unique heel construction that covers the heel counter as viewed from the outside. I tested a size 9 after trying some 9.5’s that I’d usually wear- they felt large.
The unstructured upper is achieved through extensive use of high frequency welding, a process of joining fabrics without stitching that enables shoe and clothing designers to do things with welded seams that are impossible with stitched seams. Welded seams are lighter weight too, since you aren’t adding thread to the seam. Arcteryx and Mountain Hardwear pioneered the use of welded seams in technical garments and Karhu does well to incorporate this technology into their uppers.
Karhu shoes in general are a fresh breath in a tired category. Their technology is easy to differentiate in just a short test run, and produces benefits for triathletes missing from most other shoes except perhaps Zoot, namely, benefits for running on tired legs. The Karhu Fast 2 Fulcrum Ride I ran in most recently were exceptionally tuned for a comfortable, efficient run out of T2 on tired legs.
Karhu Fast 2 Fulcrum Ride Ratings:
Shoe fit: Tom Demerly’s Rating: “★★★★” 4 Stars of Five. Runs slightly large due to relaxed upper construction. Moderate width.
Shoe Stability: Tom Demerly’s Rating: “★★★★” 4 Stars of Five. This isn’t intended to be a stability shoe, and it allows your foot to go where it will needs to on tired legs.
Shoe Cushion: Tom Demerly’s Rating: “★★★★★” 5 Stars of Five. This may be the best in class cushion ride of the year. The cushion reduces vertical movement while absorbing shock. Perfect for running on tired legs, great Ironman or high mileage shoe.