Design of contents for developing an intervention app for sarcopenia in older adults: A research study using the Delphi technique

Article information

J Korean Gerontol Nurs. 2024;26(4):370-381

Publication date (electronic) : 2024 November 30

doi : https://doi.org/10.17079/jkgn.2024.00458

Hee Jung Kim¹, Ju Young Ha^,2

¹Master Student, College of Nursing, Pusan National University, Yangsan, Korea

²Professor, College of Nursing, Pusan National University, Yangsan, Korea

Corresponding author: Ju Young Ha College of Nursing, Pusan National University, 49 Busandaehak-ro, Mulgeum-eup, Yangsan 50612, Korea TEL: +82-51-510-8332 E-mail: jyha1028@pusan.ac.kr

Received 2024 May 16; Revised 2024 August 30; Accepted 2024 November 23.

Abstract

INTRODUCTION

METHODS

2. Participants

In the Delphi technique, expert opinions can serve as the primary data source for the study; therefore, participants must be selected based on sufficient background knowledge and experience [15]. Accordingly, this study targeted experts with at least 3 years of research or practical experience in fields related to sarcopenia in older adults, considering professional expertise and representativeness [17]. To ensure the reliability of the Delphi survey, a participant number between 5 and 20 is recommended [16]. Thus, this study comprised 13 experts: four nurses, three doctors, three exercise specialists, and three nutritionists. The average age of the participating experts was 39.85±8.97 years, with seven males (53.8%) and six females (46.2%). The average experience in sarcopenia-related research or practice was 12.00±8.96 years. In terms of educational background, two participants held doctoral degrees (15.4%), seven held master’s degrees (53.8%), and four held bachelor’s degrees (30.8%). Table 1 presents the general characteristics of the experts.

Table 1.

General Characteristics of the Expert Panel (N=13)

4. Measurements

1) Draft Development

To draft the initial Delphi survey, the researcher and nursing professor reviewed domestic and international literature and resources. The analysis included current sarcopenia intervention apps for older adults in Korea, specialized publications by the Korean Sarcopenia Society, and other related literature on sarcopenia interventions, resulting in the identification of three main categories (sarcopenia assessment, exercise intervention, and nutritional intervention) and 14 subcategories for sarcopenia intervention content (Table 2).

Table 2.

The References of Delphi Survey Draft

The sarcopenia assessment follows the recommendations of the Asian Working Group for Sarcopenia (AWGS) and includes three items: the SARC-F questionnaire (assessing strength, assistance in walking, rising from a chair, climbing stairs, and falls), calf circumference measurement, and the five-time chair stand test [3,7]. Exercise intervention includes flexibility, aerobic, and resistance exercises. Flexibility exercises can be classified into two categories: dynamic and static stretching. Aerobic exercises include two items: rhythmic movements set to music and Saecheonyeon Health Exercises. Resistance exercises are divided into four categories, with upper and lower body exercises using resistance bands and dumbbells [7-9,13]. The nutritional intervention includes dietary management education (identifying personal eating habits, maintaining regular meal times, reducing sugar and salt intake for health), along with recommendations for consuming essential amino acid-based proteins at 1.2~2.0 g/kg to maintain muscle mass and strength, and a daily intake of over 800 IU of vitamin D [7,9].

2) Delphi Survey Process

The Delphi survey, conducted over two rounds from October 2023 to January 2024, was designed to gather expert opinions, as it has been noted that 2~3 rounds are typically sufficient to achieve expert consensus [16]. In the first round, the survey questionnaire was prepared by presenting the sarcopenia intervention components identified from the literature review, along with related national and international studies. For instance, the upper body dumbbell exercises included in the resistance training section consisted of movements such as “lateral raise (deltoid),” “front raise (deltoid),” “upright row (shoulders, neck, trapezius),” “curl with elbows close to body (biceps brachii),” “kick back (triceps brachii),” and “bent-over row (trapezius, arm, erector spinae),” to be performed in two sets of 10 repetitions each. The instructions included starting with a light weight and gradually increasing it, with caution against heavy loads and potential joint or muscle injuries. Benefits such as muscle hypertrophy, strength enhancement, and improved muscle endurance through fiber oxidation and mitochondrial energy production have been reported. The validity of each item was assessed using a 5-point Likert scale (1=very inappropriate, 5=very appropriate), and open-ended questions allowed participants to freely suggest revisions or additions to each item. Nurses and doctors responded to all three intervention categories, whereas exercise specialists and nutritionists responded only to the exercise and nutrition intervention sections.

The second round of the Delphi survey incorporated feedback from the first round, in which modifications were made based on the collected data and additional expert opinions. For example, in the upper body dumbbell exercises, items were revised to include “lateral raise (deltoid),” “upright row (shoulders, neck, trapezius),” “curl with elbows close to body (biceps brachii),” “bent-over kick back (trapezius, triceps brachii, erector spinae, popliteus),” “back row (latissimus dorsi),” and “lying dumbbell press (serratus anterior, pectoral muscle),” with a suggested intensity of 11~15 on the Borg ratings of perceived exertion scale. The instructions emphasized beginning with 30%~40% of the individual’s maximum weight, progressively increasing to 60%~70%, and proceeding slowly to ensure muscle activation. The perceived exertion level was clarified using instructions for moderate difficulty. As in the first round, a 5-point Likert scale was used for validity reassessment, with opportunities to comment on the modified content. Both rounds of the survey were conducted via email, and experts were asked to complete all the relevant items in their specific intervention areas.

The survey results were analyzed using the SPSS/WIN ver. 29.0 (IBM Corp.). For each content item, a mean score of 4.00 or above on a 5-point Likert scale was considered valid. The Content Validity Index (CVI) was calculated as the proportion of responses rated 4 or 5, with a threshold of 0.75, indicating acceptable content validity [18]. Stability was assessed by calculating the Coefficient of Variation (CV), defined as the ratio of the standard deviation to the mean, to gauge the degree of consensus among experts; a CV of less than 0.50 was considered an indicator of expert agreement [19].

RESULTS

1. Results of the First Delphi Survey

The first Delphi survey was conducted using a 5-point Likert scale questionnaire with 14 items derived from a literature review and reviewed by a nursing professor. Open-ended questions were included to gather suggestions for modifications and improvements. Descriptive statistics showed an average score of 4.00 or higher across all items, with two items having a CVI below 0.75, and all items having a CV below 0.50 (Table 3).

Table 3.

The Result of Delphi

In the sarcopenia assessment category, all CVI values were 1.00, indicating high validity. Based on open-ended feedback, additional content was added regarding posture, weight, or size examples, and safety precautions during measurements. For exercise interventions, all resistance exercises except for the elastic band exercise achieved a CVI of 0.80 or above. Adjustments were made to further detail these items, based on expert feedback. Flexibility exercises were modified to account for the joint mobility and strength limitations in older adults, and core and spinal exercises were added. For aerobic exercises, the order was modified to adopt a gradual approach and easily understandable terms were added to perceived exertion as an indicator of exercise intensity. The elastic band exercise, which did not meet the CVI threshold of 0.75, was removed, while additional upper and lower body resistance exercises using dumbbells, targeting major muscle groups were included. To further enhance muscle function, balance exercises suggested by experts were added along with items specifying the order, frequency, and duration of warm-up (dynamic flexibility exercises), main exercises (aerobic, resistance, and balance exercises), and cool-down exercises (static flexibility exercises).

In the nutritional intervention category, all items achieved a CVI of 0.90 or above, indicating high validity. In response to expert feedback, a component for constructing a balanced diet was added to the dietary management education. The recommended intake of amino acid-based protein was adjusted to 1.1~1.6 g/kg, and the recommended vitamin D intake was updated to 800~1,000 IU/day. A second Delphi survey was conducted using the same method to confirm the opinions regarding the revised content.

2. Results of the Second Delphi Survey and Final Draft

CVI of 1.00, while in the exercise intervention category, two items—“Flexibility Exercise 1” and “Order, Frequency, and Duration of Exercises”—achieved a CVI of 0.90, and all remaining items scored 1.00 (Table 3).

The stability of all items was confirmed, with CV values ranging from 0.06 to 0.14, below the threshold, indicating no need for further rounds. This process finalized the content into three items for sarcopenia assessment, 11 items for exercise intervention, and three items for nutritional intervention. The final design of the sarcopenia intervention app content is presented in Table 4.

Table 4.

Final Contents Configuration

DISCUSSION

This study is a survey using the Delphi technique to design content for a sarcopenia intervention app, with a focus on discussing the content developed through the Delphi process.

A two-round Delphi survey was conducted with doctors, nurses, exercise specialists, and nutritionists with research or practical experience in sarcopenia-related fields to identify the content for developing a sarcopenia intervention app. The Delphi technique is commonly used in research to select items with high validity from a large set and to derive evaluation metrics or educational content [15]. However, it is also utilized in intervention development to examine the validity and collect comprehensive expert opinions, as seen in studies by Park et al. [19] on exercise programs to improve walking ability in older adults, and by Bae et al. [20] on a remote cognitive-exercise dual-task program for community-dwelling older adults. Similarly, in this study, the Delphi technique was employed to compile expert opinions from various disciplines, gather detailed feedback through open-ended questions, and validate content using a Likert scale to design comprehensive sarcopenia intervention app content.

The app content includes sarcopenia assessment, exercise interventions, and nutritional interventions. The assessment method includes “calf circumference measurement,” “SARC-F questionnaire,” and the “chair stand test,” as recommended by the AWGS for simple assessments in primary care settings [3]. If either the calf circumference measurement or SARC-F questionnaire score is outside the normal range, the chair stand test is administered to further classify the individuals into groups for exercise and nutritional interventions [3]. In a study by Piodena-Aportadera et al. [21], calf circumference measured while standing showed high diagnostic accuracy for sarcopenia screening, whereas Kim et al. [22] verified the validity of the Korean version of the SARC-F questionnaire for community-dwelling older adults, demonstrating high specificity and negative predictive value for sarcopenia. When developing a mobile app, it is essential to incorporate safety precautions and measurement criteria as emphasized by experts to ensure the safety and accuracy of the assessment process.

In this study, the sarcopenia exercise intervention comprises warm-up, main, and cool-down exercises. Warm-up and cool-down exercises are structured with flexibility exercises to increase deep muscle temperature, promote muscle elongation, enhance joint range of motion, and prevent injuries and falls by reducing muscle soreness [7,19]. During the Delphi process, experts recommended holding each stretching position for at least 20 seconds to maximize effectiveness and suggested adding torso rotations and hip raises to the core exercises. Additionally, to increase safety, arm and spine stretches are conducted in a seated position, and hip joint stretches are modified to reduce fall risk by avoiding standing forward bends. Instead, a seated position is recommended, in which one leg is crossed over the knee and the torso leans forward, thus minimizing the balance shift. This aligns with a study by Oh and Cho [23], in which a lower-limb strengthening program for older women utilized dynamic stretching as a warm-up and static stretching for cool-down, significantly improving isokinetic strength and fall-prevention fitness factors, suggesting its applicability in sarcopenia exercise interventions.

The primary exercises in the sarcopenia intervention program include aerobic, resistance, and balance exercises. Aerobic exercise is essential as it helps reduce levels of inflammatory cytokines (interleukin-6, tumor necrosis factor-α), which are involved in the primary mechanisms of sarcopenia, and supports mitochondrial homeostasis, improving insulin resistance and slowing muscle mass loss [8]. In this study, aerobic exercises include the Saecheonyeon Health Exercise and rhythmic movements to music (such as step movements, heel taps, torso twists, and knee lifts). Similar to flexibility exercises, the Delphi process incorporates expert recommendations to begin aerobic exercises with dynamic stretching to prevent sudden blood pressure fluctuations, thereby reducing the fall risk. Additionally, a gradual approach was suggested, starting with “exercise” and progressing to “rhythmic movements,” allowing for incremental increases in intensity. This aligns with a study by Kim et al. [24], in which structured aerobic exercise with music demonstrated significant increases in upper and lower limb strength and endurance in older men, suggesting its effectiveness as a sarcopenia intervention.

Resistance exercises are crucial for enhancing the functional and structural aspects of the muscles. It commonly uses free weights such as dumbbells, sandbags, resistance bands, or body weights, and includes both upper and lower body exercises [7,8]. Resistance exercises were structured as upper and lower body dumbbell exercises. Upper body exercises target the deltoids, shoulders, neck, trapezius, biceps, triceps brachii, erector spinae, popliteus, serratus anterior, pectoral, and latissimus dorsi muscles. This composition was refined through the Delphi process to address age-related weakening of the stabilizer muscles in the shoulders, including additional exercises for the serratus anterior, pectoral, and key muscle groups such as the latissimus dorsi. The lower body exercises target the gastrocnemius, soleus, posterior tibialis, gluteus maximus, quadriceps, and hamstrings. Experts in the Delphi process recommended adding squat movements to stimulate the gluteus maximus, quadriceps, and hamstrings, emphasizing the need to prevent muscle mass and function decline in older adults, particularly in type IIx muscle fibers. Furthermore, the heel-raising exercise was modified to activate the posterior tibialis, a core muscle for foot stability, by placing a ball between the feet to engage the plantar fascia. To address the common occurrence of anterior knee pain in older adults, forward lunges were modified to backward lunges to control quadriceps strain. Resistance exercises physically stimulate muscle fibers, activate signal transduction pathways, enlarge the muscle fiber cross-sectional area, stimulate satellite cells, and promote muscle growth and strength improvement [7]. A study by Kim et al. [24] demonstrated that resistance exercises using dumbbells for the upper and lower body effectively improved muscle strength and endurance in older men, while another study by Kim et al. [25] showed significant improvement in lower body strength with resistance exercises, including modified squats, in older adults, suggesting the suitability of dumbbell resistance exercises for sarcopenia intervention.

In the initial draft, the resistance exercises included both resistance bands and dumbbells. However, through the Delphi process, experts recommended removing resistance band exercises owing to redundancy and instead suggested adding balance exercises. While resistance bands are not easily replaced by household items, Choi et al. [26], who developed a physical activity program for sarcopenia in older men, successfully replaced dumbbells with water bottles, demonstrating that resistance exercises can be adapted for long-term maintenance. Balance exercises have proven beneficial for sarcopenia interventions. For instance, Kim et al. [25] found that including balance exercises in a fall-prevention program significantly strengthened the lower body muscles in community-dwelling older adults, whereas Liang et al. [27] showed that a combined exercise program with balance exercises improved strength, physical function, and daily living activities more effectively than resistance exercise alone in patients with sarcopenia. Therefore, balance exercises are considered appropriate interventions for sarcopenia.

In this study, the nutritional intervention for sarcopenia consists of dietary habit education, protein intake, and vitamin D intake. Dietary habit education includes identifying personal eating habits, maintaining regular meal times, reducing salt and sugar intake, and following a balanced diet. The balanced diet component was added based on feedback from Delphi experts. Han and Jeon’s study [28] on low-income older adults developed and applied a nutrition education program focused on proper dietary management, reduced salt and sugar intake, and affordable, balanced meals, resulting in improved dietary habits. This is expected to prevent sarcopenia and increase muscle mass in older adults. For future app development, it would be beneficial to provide practical examples of low-sodium, low-sugar, and balanced meals, as suggested by experts, to make dietary habits education more effective for older adults.

For protein intake, this study recommends a range of 1.1~1.6 g/kg. This range reflects the Delphi panel’s view that older adults may have diverse health conditions, leading to significant variations in appropriate protein intake and that a high-protein diet could place strain on the kidneys. The PROT-AGE Study Group suggests daily protein intake of 1.0~1.2 g/kg for healthy older adults, 1.2~1.5 g/kg for those with chronic or acute illness, and more than 2.0 g/kg for severe disease or injury [7]. Additionally, Park et al. [29] found that among frail older adults without renal or hepatic disease, groups consuming 1.2 g/kg/day and 1.5 g/kg/day of protein showed improved muscle mass and physical function compared to a group consuming 0.8 g/kg/day, supporting the appropriateness of the protein intake level set in this study for sarcopenia intervention. However, when developing the app, it may be necessary to further tailor intake levels based on the presence of chronic conditions such as kidney disease.

Regarding vitamin D supplementation in nutritional intervention, Rondanelli et al. [9] reported that vitamin D helps reduce inflammatory markers, such as C-reactive protein, and enhances anabolic markers, leading to increased strength and improved physical function. The US Preventive Services Task Force also recommends an intake of at least 800 IU of vitamin D for adults over 70 years old [7]. During the Delphi process, experts advised caution regarding excessive vitamin D intake and recommended specifying the upper limit. Accordingly, the recommended range was set at 800~1,000 IU. A review by Kressel and Matsakas [30] on vitamin D supplementation for sarcopenia also concluded that 800~1,000 IU is effective for sarcopenia prevention, supporting this level as an appropriate nutritional intervention. For future app development, examples of foods rich in essential amino acids and vitamin D as well as dietary restrictions based on the underlying conditions should be provided.

Non-pharmacological interventions, such as exercise and nutritional therapy, are critical for sarcopenia, as there are currently no approved drug treatments [7]. This study designed content for a sarcopenia intervention app, incorporating both exercise and nutrition interventions. The Delphi technique minimizes psychological effects such as the band-wagon effect and halo effect that can arise in face-to-face discussions and enhances validity by allowing experts to revise initial judgments through statistical feedback and modified responses. However, a limitation of the Delphi survey is the lack of interactive discussions among experts owing to individualized response collection.

This study is significant because it derived specific practical content for a sarcopenia mobile app based on interdisciplinary expert opinions, highlighting the app’s potential as a digital therapeutic. Future developments will involve app developers to enhance usability, visibility, user adherence, and satisfaction, to create a sarcopenia intervention app based on the content designed in this study. This app could then be used as a strategy for sarcopenia prevention and management in community-dwelling older adults.

CONCLUSION

In this study, a Delphi survey was conducted with interdisciplinary experts experienced in sarcopenia-related research or practice to design the content for the sarcopenia intervention app. The resulting content aims to enable clinical usefulness by identifying individuals in need of sarcopenia interventions in community and primary care settings and promoting muscle mass, strength, and functionality improvements through effective exercise and nutritional interventions. Future studies are recommended to develop a mobile app based on the content designed in this study and validate its effectiveness as a sarcopenia intervention. Additionally, repeated studies using the developed app in various community settings, such as public health centers, targeting diverse older adult populations are suggested to accumulate data that can be used to further enhance the functionality and content of the sarcopenia intervention app.

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