Chen et al. (2017) - Effects of Descending Stair Walking on Health and Fitness of Elderly Obese Women

quiz

What type of exercise is descending stair walking (DSW), and how does it compare to ascending stair walking (ASW) in terms of metabolic demand?

DSW is an eccentric exercise and is less metabolically demanding than ASW, which is a concentric exercise [1, 2]. DSW requires less oxygen and energy expenditure [2, 3].

How long was the study and how many interventions were there?

Over the 12 weeks, participants completed a total of 24 exercise sessions.

The number of repetitions of stair walking was progressively increased each week. The study began with 2 repetitions per session.

Each repetition involved walking up or down 110 stairs, which was equivalent to five stories in the building used for the experiment

The exercise volume was gradually increased over the 12 weeks, beginning with 2 repetitions (220 stairs) and ending with 24 repetitions (2640 stairs)

What are some of the potential benefits of eccentric training?

Eccentric training can improve muscle strength and functional ability [1, 2]. It may also improve insulin sensitivity and blood lipid profiles [1, 2, 4].

What was the main purpose of the Chen et al. (2017) study?

The study aimed to compare the effects of DSW and ASW interventions on muscle strength, bone mineral density (BMD), insulin sensitivity, lipid profiles, and functional physical fitness (FPF) in elderly obese women [5, 6]. The hypothesis was that DSW would lead to greater improvements than ASW [6, 7].

What were the main independent and dependent variables in the Chen et al. (2017) study?

• Independent variable: Type of stair walking intervention (DSW vs. ASW) [6, 8]

• Dependent variables: Muscle strength, BMD, insulin sensitivity markers, lipid profile markers, FPF, resting heart rate and blood pressure, and balance [6, 8]

Who were the participants in the Chen et al. (2017) study?

The study included 30 sedentary obese women over 60 years old [7-9]. The participants were screened to ensure they did not have any pre-existing conditions or injuries that might affect the results [7, 9].

Describe the study design of Chen et al. (2017).

The study used a quasi-randomized controlled trial design with two groups: a DSW group and an ASW group. Participants performed stair walking twice a week for 12 weeks, with a progressive increase in repetitions. An elevator was used to ensure that the DSW group only walked down stairs and the ASW group only walked up stairs8....

How did the researchers measure the main outcomes in the Chen et al. (2017) study?

• Blood samples were used to assess insulin sensitivity and lipid profiles13....

• Muscle function was assessed using maximal voluntary isometric contraction (MVC-ISO) of the knee extensors14....

• Functional physical fitness was measured using standardized tests like chair stands, step tests, up-and-go, and walk tests14....

• Balance was assessed using the Biodex BioSway system14....

• Heart rate and blood pressure were measured using a sphygmomanometer14....

What were some of the controls used in the Chen et al. (2017) study?

• Type of muscle contraction using the elevator8....

• Confounding factors by asking participants to avoid vigorous activities, maintain normal diets, and not take anti-inflammatory drugs or supplements12....

• Muscle damage by progressively increasing the exercise volume10....

• They also used a familiarization session and tested the test-retest reliability of the outcome measures12....

What were the main findings of the Chen et al. (2017) study regarding the comparison of DSW and ASW?

DSW was more effective than ASW in improving resting heart rate and systolic blood pressure, bone mineral density (BMD), muscle strength, some functional fitness tests (30-s chair stand and 6-min walk), balance, insulin sensitivity and blood lipid profiles21....

• The study found no signs of muscle damage in either group25....

• The average heart rate was lower during DSW than during ASW25....

Based on the Chen et al. (2017) study, what are some potential explanations for why DSW was more effective than ASW?

May be due to:

• Increased mechanical stress on muscles and bones [25, 30, 31].

• Greater increases in lipoprotein lipase [25, 30, 32].

• Possible differences in how muscle fibers are stimulated [25, 33].

What were some of the limitations of the Chen et al. (2017) study?

Did not include:

• A sedentary control group30.

• Tracking of daily activity levels, diet, or hormonal responses25....

• The study did not examine the effects of a combination of DSW and ASW35.

What are some of the practical implications and future directions suggested by the Chen et al. (2017) study?

• DSW should be encouraged for the general population and less-fit individuals as a low-cost way to improve fitness and health25....

• Future research should examine the effects of a combination of DSW and ASW, the effects of DSW on other clinical populations, and the effects of other types of eccentric exercises25....

What were the main statistically significant findings shown in the figures of the Chen et al. (2017) study?

Figure 1: BMD, resting HR, and SBP decreased significantly more in the DSW group than in the ASW group36....

Figure 2: The DSW group had greater improvements in MVC-ISO force of the knee extensors, 30-s chair stand, 6-min walk, and balance compared to the ASW group37....

Figure 3: The DSW group demonstrated greater improvement in all markers of insulin sensitivity and lipid profiles compared to the ASW group37....