Hiking injury prevention

Hiking is one of the world’s most popular recreational pursuits. Whether you take a short hike or embark on a major expedition, the chances are that you will use a backpack to carry your essentials (flask of tea, Kendal mint cake, etc). While there are many positive effects to be gained from taking to the hills, hiking is often not an injury- or pain-free pastime – with lower limb joints and muscles being the obvious vulnerable spots.

Indeed, the forces generated by a combination of a heavy backpack, undulating terrain and significant amounts of downhill walking expose the body to impacts similar to those experienced during running.

This isn’t such a huge problem if you are already fit, but hiking is a mass participation pursuit and many of its adherents may not be in great physical condition. Research has already shown that the use of hiking poles can reduce the forces placed on the lower limbs. Now, a team based at the University of Western Illinois has investigated how useful these poles are if you are carrying a heavy pack. (Effects of hiking downhill using trekking poles while carrying external loads, Medicine & Science in Sports & Exercise2007: 39 (1) 177-183).

Fifteen male hikers who volunteered for the study were required to walk down a 20-degree gradient. All participants repeated this exercise while wearing a large expedition pack (30% of participant’s body weight), a smaller day pack (15% of body weight), and no backpack, while using two hiking poles and no hiking poles.

The results showed that the use of trekking poles was effective in reducing many of the contributing factors to pain and overuse injuries during downhill hiking. The use of poles helps to reduce muscle activity around the ankle and knee and limits potentially damaging loading at the hip. The study also showed reductions in eccentric loading of the lower limb musculature, thereby reducing the potential for damage at a cellular level and problems associated with DOMS (delayed onset muscular soreness).

It would appear that the trekking poles reduce the loading through two mechanisms: absorption of some of the potentially damaging impact forces; and increasing the walker’s stability.

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A daily balancing act

Balance training is a relatively new concept in the fitness industry and a research team at San Diego State University wanted to establish if a four-week balance training programme could improve functional performance in healthy, recreationally active individuals (Effects of balance training on selected skills, Journal of Strength and Conditioning Research2006: 20 (2) 422-428).

Thirty-six recreationally active volunteers took part in the study. All subjects completed a pre-test, a post-test and a retention test designed to determine whether individuals experienced a positive response from balance training and whether any positive effects lasted for two weeks after the end of training.

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The subjects were placed into two groups (control and training). The training group used a Bosu (Both Sides Up balance trainer – a solid plastic base integrated with an inflatable rubber bladder that resembles a halved swiss ball), three times a week for approximately 20 minutes. For its training protocol the study used a commercially developed training programme that had been provided with the Bosu at the point of sale.

The team assessed limb dominance and postural control measures (quiet stance and lean test) in conjunction with three functional tasks:

* time on Bosu

* shuttle run

* vertical jump.

The results showed that balance training improved performance of selected activities (time on Bosu and shuttle run), and postural control measures (quiet stance and lean test). However, the retention test indicated that any benefits gained from balance training were transient in nature – they did not last the two weeks.

This study’s results suggest that balance training can improve performance of dynamic skills and sway parameters, and may give the individual an enhanced sense of control. Do these skills transfer to other activities? While we don’t know the answer to that, it would make sense that if the training stimulus is appropriate, there should be a transfer of training effect to other activities. The key thing to note is that any improvements are short-lived – with balance improvements, you will lose it if you don’t use it.

Cherry ripe

So you’ve decided that trekking is your thing. You’ve bought your poles and incorporated a balance and proprioception training programme into your workouts. Is there anything more you can do to avoid the all-too-likely first and second days’ symptoms of activity induced muscle soreness? Researchers in Vermont think that there is.

Consumption of approximately 45 cherries a day has been shown to reduce circulating concentrations of inflammatory markers in healthy men and women. Considering the natural anti-inflammatory and antioxidant capacity of tart cherries, it is not unreasonable to think that cherry consumption before and after eccentric exercise (such as lots of downhill walking with a backpack over rough terrain) may have a protective effect. Researchers based in the Human Performance laboratory at the University of Vermont decided to put cherries to the test and discovered that a cherry juice blend can decrease some of the symptoms of DOMS (Efficacy of a tart cherry juice blend in preventing the symptoms of muscle damage, British Journal of Sports Medicine2006: 40, 679-683).

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Fourteen male students drank 12 fl oz of the cherry juice blend (freshly prepared tart cherry juice mixed with apple juice, the equivalent of 50-60 cherries) or a placebo drink, twice a day for eight consecutive days. A bout of eccentric elbow flexion contractions was performed on the fourth day of the supplementation. Isometric strength, pain, muscle tenderness and relaxed elbow angle were recorded before and for four days after the eccentric exercise.

No differences in muscle tenderness or relaxed elbow joint angle were found, but rather surprisingly the wonder juice did have some potent effects. Cherry juice drinkers had significantly less loss of strength and pain than the placebo group. Most notably strength loss averaged over the four days after the eccentric exercise was 22% among the placebo group but 4% for the cherry guzzlers.