Exploring Muscle Activation during Nordic Walking: A Comparison between Conventional and Uphill Walking.

Barbara Pellegrini,Lorenzo Bortolan,Federico Schena,Chiara Zoppirolli,Leonardo Alexandre Peyré-Tartaruga,Hélène Figard-Fabre,Elisabetta Bacchi,David Carrier

doi:10.1371/journal.pone.0138906

Barbara Pellegrini, Lorenzo Bortolan + Show 6 more

Open Access

https://doi.org/10.1371/journal.pone.0138906

Copy DOI

Abstract

Nordic Walking (NW) owes much of its popularity to the benefits of greater energy expenditure and upper body engagement than found in conventional walking (W). Muscle activation during NW is still understudied, however. The aim of the present study was to assess differences in muscle activation and physiological responses between NW and W in level and uphill walking conditions. Nine expert Nordic Walkers (mean age 36.8±11.9 years; BMI 24.2±1.8 kg/m2) performed 5-minute treadmill trials of W and NW at 4 km/h on inclines of 0% and 15%. The electromyographic activity of seven upper body and five leg muscles and oxygen consumption (VO2) were recorded and pole force during NW was measured. VO2 during NW was 22.3% higher at 0% and only 6.9% higher at 15% than during W, while upper body muscle activation was 2- to 15-fold higher under both conditions. Lower body muscle activation was similarly increased during NW and W in the uphill condition, whereas the increase in erector spinae muscle activity was lower during NW than W. The lack of a significant increase in pole force during uphill walking may explain the lower extra energy expenditure of NW, indicating less upper body muscle activation to lift the body against gravity. NW seemed to reduce lower back muscle contraction in the uphill condition, suggesting that walking with poles may reduce effort to control trunk oscillations and could contribute to work production during NW. Although the difference in extra energy expenditure between NW and W was smaller in the uphill walking condition, the increased upper body muscle involvement during exercising with NW may confer additional benefit compared to conventional walking also on uphill terrains. Furthermore, people with low back pain may gain benefit from pole use when walking uphill.

Highlights

Nordic Walking (NW) is a form of physical activity where conventional walking is supported by the use of specially designed poles
Post hoc analysis revealed that upper body muscle activation was increased from W to NW in both the level and uphill walking conditions; activation of the GL muscle was decreased in the level and uphill walking conditions, with a decrease in root mean square amplitudes (RMS) values of 12% and 15%, respectively (Fig 2)
Oxygen uptake was greater during NW than conventional walking at the same speed, with an estimated extra energy cost of about 23% during level walking at 4 km/h and of 7% during uphill walking

Summary

Introduction

Nordic Walking (NW) is a form of physical activity where conventional walking is supported by the use of specially designed poles. Energy expenditure at a given speed is about 20% higher when walking with poles [1,2,4], with the amount of the differences depending on technical and equipment-related factors. Energy expenditure depends on pole weight [7] and length [6]. The extra energy cost of using poles is related to ground surface conditions [8] and terrain slope, which explains the significant slope x pole use interaction effect on energy expenditure. A smaller difference in energy expenditure between walking with and without poles was found during walking on moderate (5%) [3] and steeper (~21%) inclines [6]. No studies to date have explained the reason for this observation

Objectives

Results

Discussion

Conclusion