The convenience of modern life in the 21st century has substantially altered our exercise behavior and habits, resulting in a constant increase in exercise participation. The statistics released by the Taiwan Sports Administration, Ministry of Education (2018) reveal that 33.6% of Taiwan’s population exercise regularly, and the total number of people who exercise is increasing annually at a steady pace. In addition, although the proportion of women who exercise (82.5%) is marginally lower than that of men who exercise (84.8%), this gap is gradually decreasing each year.
Because of aging and technological advances, the various functions of the human body are gradually exhibiting signs of degradation. In addition, the incidence of chronic disease symptoms (e.g., obesity, hyperlipidemia, hypertension, and diabetes) has been increasing (Wen & Chang, 2013). Studies have indicated that improving physical fitness is conducive to the prevention of various chronic diseases. Nonetheless, engagement in high-intensity exercise may overburden the body and cause adverse effects. Taiwanese people run and cycle, which are activities that require intense knee movement. The lack of proper exercise intensity management and application of improper exercise techniques both increase the risk of lower limb injuries (Wang, 2012).
Running mainly works the lower limbs. Because most people today prefer simple and efficient exercises, walking has become popular exercise that does not require any equipment, can be performed at any time, and can achieve a target exercise intensity without substantial effort. The American Heart Association (2011) reported that walking improves the physical health of people and increase their physical activity level. Weight-bearing exercise helps to maintain bone density and places less stress on the joints. The American College of Sports Medicine (2011) describes walking exercise as follows:
- walking exercises the major muscle groups, which include the knee extensor, gluteus extensor, and muscles in the lower extremity (e.g., gastrocnemius, soleus, and tibialis anterior).
- facilitates blood flow back to the heart, thereby improving body circulation.
- improves both muscle endurance and dynamic equilibrium.
Nordic walking is an innovative walking types that originated from the technique used by cross-country skiers for summer training. Nordic walking first received attention in 1930, and thereafter, people started to study the advantages and benefits of this walking types (Jódar Reverte, 2019).
Nordic walking differs from usual walking in that poles are used to propel the body forward. As an emerging fitness technique, Nordic walking has gradually become a leisure and health/fitness improvement option for people, particularly older adults. Individuals can maximize the benefits of exercise through walking. The Federación Española de Deportes de Montañay Escalada 〔FEDME〕(2018) recognized Nordic walking as a dynamic and rhythmic exercise that is suitable for people of all ages. According to FEDME regulations, Nordic walking competitions are usually conducted on routes measuring between 10 and 42 km.
Nordic walking is an activity that involves the use of poles mainly to support the upper and lower body and ensure joint alignment, thereby reducing the impact of walking on the joints (Padulo et al., 2018). It requires a walker to hold a pair of poles at approximately handshake height in front of them. Approximately 50% of the human muscles are in the upper body, and the primary focus of Nordic walking is on exercising the upper body muscles. With each step, people push off with the poles (in opposite directions) to work and tighten the arm muscles, abdomen, back, and chest muscles, thereby performing a full-body exercise (Huang, 2016).
Nordic walking effectively works 90% of the body’s muscles. Therefore, it is a full-body aerobic exercise (Wen & Chang, 2013). Nordic walking involves walking while using poles in both hands for support, which sets it apart from conventional power walking. The two poles are used for supporting, stretching, and extending both arms. Therefore, the upper body muscles are exercised, and arm strength is applied. In a comparison of Nordic and usual walking on a treadmill, Hansen and Smith (2009) discovered that older adults exercise more upper body muscles and consume more calories during Nordic walking than during usual walking.
Parkatti et al. (2012) also proposed that relative to usual walking, Nordic walking is approximately 20% more effective at strengthening the upper body muscles and improving the circulation of older adults because it involves the use of poles. In addition, Nordic walking can improve gait balance and stability. Willson et al. (2001) reported that the use of walking poles can effectively increase stride length and frequency, thereby increasing walking speed by approximately 3.6%. Moreover, relative to usual walking, Nordic walking can reduce the impact of the ground reaction force on the feet and knee joints by 4.4%, which effectively reduces knee joint load.
Dalton and Nantel (2016) implemented a Nordic walking intervention for older adults (8 female and 4 male participants) that comprised two weekly sessions over 8 weeks. Each session involved two 6-min walk tests and six 5-m walk trials (three with the use of poles and three without the use of poles). After the intervention, participants exhibited increased stride length, higher stride frequency, and enhanced strength in hip and knee joint muscles.
The literature has mostly focused on health improvement among older adults and special populations including people with diabetes (Balady et al., 2010;Pippi et al., 2020) , cardiovascular diseases (Launois et al., 2018), obesity or overweight (Hagner-Derengowska et al., 2015), and neurological disorders (e.g., Parkinson’s disease) (Monteiro et al., 2017). Most studies have indicated that Nordic walking is a relatively simple exercise that can offset the negative effects of inactivity and assist patients in improving their physical health (Ben Mansour et al., 2018).
Few studies have discussed the benefits of Nordic walking for healthy middle-aged people. In addition, most studies conducted treadmill-based experiments. The present study enrolled healthy middle-aged women as participants to explore the effects of walking types on muscle activation and gait parameters.