Load Carriage Comparison Between Standard and Anti-Shock Trekking Poles
Load Carriage Force Production Comparison Between Standard and Anti-shock Trekking Poles
ISSN: 1543-9518
Bert H. Jacobson, Jennifer Kaloupek & Doug B. Smith
Medicine & Science in Sports & Exercise Supplement to VOL. 24, NO.5, May 1992
Purpose: To compare the use of standard, anati-shock, and no hiking poles on medio-lateral (Fx), anaterio-posterior (Fy) and vertical (Fz) ground reaction forces for the foot and hiking poles while during load carriage walking at 0% grade. Methods: Subjects were solicited from experienced backpackers who had used hiking poles for at least 5 years. Each subject was fitted with an 18 kg internal frame backpack and allowed to practice walking with and without hiking poles to a metronome cadence equal to a walking speed of 4.42 Km.hr-1. During each successful trial the subjects contacted a piezoelectric force plate positioned in the floor with the foot and contralateral hiking pole. Three trials were conducted in random order 1) without hiking poles (NP), 2) with standard (SP) hiking poles, and 3) with anti-shock (AP) hiking poles. For each trial the following data were recorded: 1) Medio-lateral (FFx), anterior-posterior (FFx), and vertical (FFz) ground reaction force for the foot medio-lateral (PFx), anterior-posterior (PFx), and vertical (PFx) pole forces. Results: No significant differences in foot reaction forces were found among the three conditions (NP, SP, and AP) for any of the recorded dimensions (medio-lateral, anterior-posterior, and vertical). Also, no significant differences in force parameters was evident between the two types of hiking poles. Conclusion: No significant weight transfer from lower to upper body was evident regardless of pole design indicating that dependency on hiking poles during load carriage walking on level ground is negligible.
The use of hiking or trekking poles has become popular with both the weekend recreational hiker as well as the serious hiker. As early as 1996, 49% of hikers in the Austrian and Italian Alps were using “trekking poles” (Rogers et al, 1995). Over the last few years, hiking poles have evolved from simple, single walking sticks to dual, spring-loaded, telescopic poles equipped with wrist straps and carbide tips. Manufacturers of hiking poles have made largely unsupported and anecdotal claims of the benefits of employing hiking poles while hiking. Such claims as extra balance, surer walking, and reduction of stress are common (Jacobson et al, 2000). The claim supporting “reduction of stress” on lower limbs (Haid and Koller, 1995; Wilson et al, 2001) stems from the belief that part of the load is transferred from the legs to the arms and shoulders Neurether, 1981).
Previous studies involving hiking poles have included mixed protocols. For instance, some hiking poles with such names as Exerstriders® and Power PolesT are marketed for the purpose of increasing fitness parameters and caloric expenditure rather than for hiking activity by suggesting exaggerated arm swing. In a study using Power PolesT, Porcari and associates (1997) measured selected physiological variables during a 20 minute treadmill test at self selected speed and grade and found significant increases in oxygen consumption (VO2), respiratory exchange, caloric expenditure, and heart rate. In another study Rodgers and associates8 found that using Exerstriders® while walking for 30 minutes, at 6.7 km.hr-1 on 0% grade with exaggerated arm swing significantly increased VO2, and HR by 12% and 9% respectively.
However, in two separate studies utilizing hiking poles in a traditional hiking manner and without excessive arm motion, both groups of researchers found no significant differences in oxygen consumption between pole and no pole use during a 1 hr, 5% inclined treadmill walk with a 22.4 kg backpack (Knight and Caldwell, 2000) or during a 15 min. inclined (10%-25%) treadmill walk while carrying a 15 kg back pack (Jacobson et al, 2000). Also Jacobson and associates (2000) found no differences in minute ventilation (VE) or caloric consumption (Kcal.min-1 ) between pole and no pole conditions. Some authors have found greater heart rate (Neurether 1981; Procari et al, 1997; Sklar et al, 2003) with pole use, while others have reported no significant differences in heart rate between pole and no pole use (Jacobson and Wright, 1998; Jacobson et al, 2000). It has been suggested that discrepancies in results may be due to the variations in research protocols among the studies.
While there is general agreement that hiking poles do not reduce energy utilization and may, if used in an exaggerated manner, increase energy utilization as illustrated by caloric consumption, ventilation, and heart rate. With respect to rating of perceived exertion (RPE), the predominance of literature (Jacobson and Wright, 1998; Jacobson et al, 2000; Knight and Caldwell, 2000) suggest that walking with hiking poles provide an impression of reduced exertion when compared to not using hiking poles. It is possible that the perception of reduced exertion when using hiking poles results from an increase in stability provided by the additional points of contact (Neurether, 1981). Jacobson and associates (1997) found that stability and balance was significantly improved with the use of both one and two hiking poles.
Early claims that hiking poles reduces the overall stress on the limbs by transferring the weight to the arms and ultimately to the poles (Haid and Koller, 1995; Unione Internazionale, 1994) were largely unsupported until recently. Schwameder et al (1999) examined external and internal loads on the knee joint during declined (25%) walking with and without hiking poles and found significant differences in peak and average magnitudes of ground reaction forces, knee joint movement, an dtibiofemoral compressive and shear forces with pole use. Wilson and associates (2001) found a decrease in average vertical ground reaction force (Fz) while using walking poles at self-selected speeds. This decrease in vertical ground reaction force was evident for two separate poling conditions when compared to using no poles.
The purpose of this study was to compare differences in load bearing, three dimensional foot and hiking pole ground reaction force between standard, anti-shock or no hiking poles while during 0% grade walking.
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