Nordic walking training in elderly, a randomized clinical trial. Part II: Biomechanical and metabolic adaptations

Abstract

Background: Nordic walking is an attractive method of endurance training. Nevertheless, the biomechanic response due to the additional contribution of using poles in relation to free walking training has been less explored in the elderly.

Purpose: This randomized parallel controlled trial aimed to assess the effects of 8 weeks of Nordic walking and free walking training on the walking economy, mechanical work, metabolically optimal speed, and electromyographic activation in elderly.

Methods: Thirty-three sedentary elderly were randomized into Nordic walking (n = 16) and free walking group (n = 17) with equalized loads. Submaximal walking tests were performed from 1 to 5 km h-1 on the treadmill.

Results: Walking economy was improved in both free and Nordic walking groups (x2 4.91, p = 0.014) and the metabolically optimal speed was increased by approximately 0.5 km h-1 changing the speed-cost profile. The electromyographic activation in lower and upper limbs, pendular recovery, and total, external, and internal mechanical work remained unchanged (p > 0.05). Interestingly, the internal mechanical work associated with arm movement was higher in the Nordic walking group than in the free walking group after training, while the co-contraction from upper limb muscles was reduced similarly to both groups.

Conclusions: Eight weeks of Nordic walking training effectively improved the walking economy and functionality as well as maintained the gait mechanics, similar to free walking training in elderly people. This enhancement in the metabolic economy may have been mediated by a reduction in the co-contraction from upper limb muscles.

Trial registration: ClinicalTrails.gov NCT03096964.

Keywords: Aging; Cost of transport; EMG co-activation; Inverted pendulum recovery; Mechanical energy fluctuations; Oxygen consumption; Walking with poles.

Conflict of interest statement

The authors, Natalia Gomeñuka, Henrique Oliveira, Edson Silva, Elren Monteiro, Rodrigo Rosa, Alberito Carvalho, Rochelle Costa, Martín Paz, Barbara Pellegrini, and Leonardo Peyré-Tartaruga, declare that they have no competing interests.

Figures

Fig. 1

Trial design and experimental procedures in the different moments of the present study

Fig. 2

Flowchart of the study participants

Fig. 3

The left column is the example of the behavior of BCoM energies during treadmill walking (without poles) at 3 km h−1, at the pre- and post-training moments. Top panel PE and KE, and TE = PE + KE, lower panel R%(t) indicating the conversion percentage of the pendulum mechanism during the step time cycle. Divided lines FW group and continuous lines NW group, left and right side of the figure of the BCoM energies represent the pre- and post-training moment, respectively. In the right column are the results of the Wint_legs, Wint_trunk, and Wint_arms of FW and NW groups in pre- and post-training moments, in the different speeds (results are in mean values, for more information see Table 4)

Fig. 4

Result of the cost of transport (C, left vertical axis) and Recovery (R, right vertical axis) at different walking speeds. Results are presented as mean, white and black circles with continuous lines and light gray square and dark gray square with continuous lines represent C values from the FW group and NW group in pre- and post-training moments, respectively. White and black diamond with dotted lines and light gray and dark gray triangles with dotted lines represent R values from the FW group and NW group in pre-and post-training moments, respectively. The white and black arrows represent the optimal speed (OPT that is the speed at the minimal C of walking) of FW group (from pre- to post-training was from 3.50 to 4.04 km h−1 ), and the light gray and dark gray arrows represents the OPT of NW group (from pre- to post-training was from 3.81 to 4.29 km h−1). * Symbol between white and black arrows united by the continuous indicator and the * between light gray and dark gray arrows united by the indicator with dotted line represents significant difference (p < 0.05) in factor time in OPT of FW and NW group (from pre to post-training), respectively

Fig. 5

Example of the behavior of the mean amplitude of the signal normalized by the percentage of the stride throughout the different speeds of one subject from NW group (left side) and one subject from FW group (right side) in pre- and post-training moments (in continuous and dotted lines, respectively). Data presented in means (black lines) ± 1SD (gray lines). Note: AD, TB, VL, BF, AT and MG represents the anterior deltoid; the triceps brachii; the vastus lateralis; the biceps femoris; the anterior tibialis and the medial gastrocnemius muscles, respectively

Fig. 6

Representative curves for one subject (NW group at post-training) of the muscular co-contraction analysis. The co-contraction is the overlap area on antagonist muscles