An Investigation of the Restorative Benefits of Different Spaces in an Urban Riverside Greenway for College Students—A Simple Autumn Outdoor Experiment

Abstract

Greenways are important natural environment places in cities, which have a great restorative effect on human physiological and mental health. The restoration effect of urban greenways on the physical and mental health of urban residents is affected by the type of greenway space. In order to reveal the restorative effects of different types of urban waterfront greenway spaces on the human body and explore restorative environmental factors, this paper firstly used the expert survey method to construct an AHP (analytic hierarchy process) model, which yielded three types of criterion-level indicators and eight types of sub-indicators. Second, taking Nanxun Avenue Greenway in Wenjiang District, Chengdu City, Sichuan Province, China, as an example, it was divided into three types of greenway spaces—waterfront space, underwood space, and lawn space—on the basis of field surveys. A total of 30 subjects participated in this outdoor experience and collected their physiological and psychological data. The results of the experiment showed that all three types of spaces in the Nanxun Avenue Greenway had a restorative effect on human physical and mental health, and all of them were effective in lowering blood pressure and heart rate, as well as eliminating negative emotions and increasing positive emotions for most of the participants. The waterfront space had the best restorative effect, followed by the underwood space and the lawn space. The main restorative environmental factors differed among each of the three types of spaces. This paper provides insights and examples for exploring the restorative benefits of urban greenways.

1. Introduction

The concept of “restorative environments” was first introduced to the world in 1983 and is defined as restorative environments that better manage mental fatigue and stress-related negative emotions. The attention restoration theory (ART) suggests that human beings have an innate desire for natural environments, and that instead of decreasing their attention span, they can recover from mental fatigue when they are in natural environments [1]. Another theory about restoring the environment, “Stress Reduction Theory” (SRT), suggests that when people in a state of stress are enjoying natural landscapes, it can reduce the overconcentration of the crowd’s attention, and the stress can be relieved, and not directly restore attention, but relieve the stress [2]. Urban green spaces (UGSs) are important places for residents to be close to and experience nature and are widely recognized as an important part of the urban environment, with a positive impact on public health [3]. These environments have a positive effect on fostering positive emotions [4], relieving anxiety and stress [5], enhancing cognitive abilities [6], and reducing morbidity and mortality from cardiovascular and respiratory diseases [7]. Among all green spaces, greenways are particularly prominent [8]. In the academic literature, a greenway is defined as “a network of land containing linear elements that are planned, designed, and managed for a variety of purposes, including ecological, recreational, cultural, aesthetic, or other purposes consistent with the concept of sustainable land use” [9].

Urban greenways are multi-functional green corridor networks formed by connecting various natural or artificial elements in the urban spatial environment, which can avoid habitat fragmentation, maintain the integrity of natural ecosystems, and help congested cities to improve opportunities for positive interactions between humans and nature, making them an important part of the UGS [10,11,12]. It is crucial for urban ecological protection and optimization, and recreational development [13]. Urban greenways can better meet the recreational and fitness needs of residents and become an important place for daily leisure activities for urban residents [14]. Therefore, urban greenways may have different functions from other UGSs, enabling them to integrate natural resources while promoting public health restoration. It is useful to study the restorative nature of urban greenways in order to provide nature-based solutions for high-quality urbanization [15]. Greenway landscapes typically include elements such as vegetation, water bodies, and topography, as well as visual attributes such as shape, color, texture, scale, and alignment of these elements [16]. Among the physical features, trees are particularly influential, providing valuable landscape features when viewed horizontally or traversed [17]. Water bodies, another key element in the greenway landscape, contribute positively to the visual experience due to their visibility and strategic location in the landscape [18]. Whether they are rivers, lakes, or well-designed manmade water features, they enhance the overall pleasure and visual enjoyment of their surroundings [19]. According to restorative theory, Hartig (2004) defined restorative environments as spaces where individuals can disengage and relax, promote positive restorative effects, and provide a means of escape from daily life [20]. A large number of empirical studies on landscape restorativeness have shown that different morphological features, environmental elements, and spatial types of green spaces have different degrees of influence on human health recovery [21,22,23,24,25,26,27]. Compared with urban environments, natural environments are more likely to promote health recovery. However, not all natural environments exhibit the same level of restorative properties [28], and there are differences in the restorative properties of various elements of natural environments. The topographic landscape of natural mountain forests is highly restorative [21]. Improving the quality of elements such as trees, lawns, flowers, and water bodies is a reliable way to increase the restoration benefits of UGS [29]. In summary, UGSs have different restoration benefits and different types of green environments have different restoration potentials due to differences in environmental characteristics. Landscapes with a variety of natural elements may provide better restoration because they are more likely to meet different needs and provide resources for a variety of restoration experiences.

Urban greenways are a special type of UGS, and urban riverside greenways are a special type of urban greenway type [12,30]. Most of the current studies on urban riverside greenways explore the interactions among humans, greenways, and environment and landscape enhancement from the perspectives of multidimensional sensory perception [18,31,32,33], socioecological service capacity [34], environmental characteristics [35], and use evaluation [36,37], and there is a lack of studies and explorations on environmental restorativeness of green spaces [38,39,40]. This suggests that the impacts of urban riverside greenways on public health may need to be assessed in more detail and concretely, rather than investigating their impacts on health at an abstract, general level [11]. Further, does the urban riverside greenway landscape play the same restorative role as other natural environments in relieving human stress and relieving negative emotions? What are the effects of different space types of greenways on human physical and mental recovery? The roles played by the main environmental factors of different types of greenway spaces are still the focus of in-depth attention and research. Therefore, there is still a gap in the understanding of the correlation between physical and physiological recovery among humans, greenways, and the environment, and this study aims to explore the interactions between them.

The analytic hierarchy process (AHP) is a system evaluation method for optimizing and evaluating systems with different object attributes and complex structures that are difficult to fully quantify [41]. This method was originally proposed by T.L. Saaty, an American operations research fellow and professor at the University of Pittsburgh; it is flexible, systematic, and concise, and has been widely used in many fields [42,43,44,45,46,47,48], including the research scope of the discipline of urban planning and landscape ecology [49,50].

In this study, blood pressure and heart rate measurements, which can reflect the physical and mental changes in subjects, were added to the subjective evaluation scale for quantitative research. By subdividing three different types of urban greenway space—waterfront space, underwood space, and lawn space—the aim of this study was to investigate the differences in physiological and psychological effects of different types of spaces on the human body in urban greenways, as well as to explore the causal relationship between various restorative environmental factors and human stress release within each space, and to summarize the restorative effects of urban greenway spaces.

This study mainly explores the following two questions: (1) What are the differences in the restorative effects of different space types on human health in urban riverside greenways? (2) What are the main restorative factors of different spatial types of urban riverside greenways?

The innovation of this study is to enhance the landscape experience quality of the greenway space from the perspective of restorative environmental factors through the combination of analytic hierarchy process (AHP) and restorative experimental research, which provides a theoretical basis for the future planning and configuration of urban riverside greenways. This work will enable more targeted construction of restorative environments along the greenway, improve the quality of restorative experiences for residents, and provide evidence-based practice for realizing the goal of human-centered habitat construction.

2. Material and Methods

2.1. Research Objects

The study area is located in Wenjiang District, Chengdu City, China. The terrain is flat and belongs to the western part of Chengdu City District, which is an important part of Chengdu City. It has abundant water and grass, no hills, high biodiversity, abundant resources, and unique natural ecological conditions, making it known as the “green lung of the city”.

Greenways are selected based on the following criteria:

(1)

The residents can easily reach the greenways for recreation.

(2)

The greenway should be built within 20 years, so that the quality of greenway construction and adequate infrastructure can be guaranteed to a certain extent.

(3)

The greenway should not leave the greenery and water bodies, and the researched greenway should have a certain amount of vegetation and a certain area of water space.

Therefore, the final location of the experiment was set as the Nancheng Nanxun Avenue Greenway (NAG) in Wenjiang District, Chengdu City. Through this experimental research, it can be seen that the greenway is in the center of the city, accompanied by the Jiang’ an River, with a total length of about 11 km; rich in landscape; surrounded by many commercial buildings and neighborhoods; with a wide variety of plant species and relatively dense; a hydrophilic waterfront barge; clean and natural water features; and a relatively high frequency of usage. Therefore, this choice also has some real-life significance (Figure 1).

Waterfront space corresponds to blue space in urban space theory. This study defines the greenway waterfront space as the greenway space in the greenway that is adjacent to a large body of water and is able to come into close contact with the body of water.

This study defines underwood space as the space in the greenway that has more than 60% vegetation cover and 50% or more depression.

This study defines lawn space as follows: in the greenway, the area on both sides of the road that is dominated by lawn area, with a small number of trees and shrubs, and the projected area of trees and shrubs shall not exceed half of the lawn (

Table 1. Information on the three spaces of the NAG.

Research Space	Waterfront Space	Underwood Space	Lawn Space
Landscape type	Water body	Midwood	Lawn
Landscape element	Mainly lakes, trees, shrubs, lawns, greenway, natural revetment	Mainly for trees, shrubs, greenway, landscape pieces, rest facilities, rivers	Mainly for trees, shrubs, lawns, greenway, landscape pieces
Spatial features	Close proximity to bodies of water, linear spaces with the richest landscape elements, moderate sky visual index	Linear narrow space, farther away from water bodies, lower sky visual index	Open space, farther away from water bodies, highest sky visual index

).

2.2. Participants

The aim of this study is to solve the health problems of urban residents as well as to explore the effect of different landscape restorative environments of greenways on the recovery of human health. Thus, the object of this study is long-term sedentary, university students who spend long amounts of time away from the natural environment and lead stressful college lives. The same college and university students have high accessibility to and a certain amount of knowledge reserves, which can be better matched with this study. According to the central limit theorem, when the sample size exceeds 30, the sampling distribution of the mean tends to be normally distributed. Therefore, 30 school students were called as volunteers in this study, with a male-to-female ratio of 1:1, aged 18–24 years old. All participants had normal senses and were free from any mental and physical illnesses. During the experimental period, no medication was taken, and they were asked to avoid smoking and drinking as well as strenuous exercise.

2.3. Methods, Data, and Variables

2.3.1. Construction of Evaluation Indicators for Restorative Environmental Factors

The restorative environment factor is based on attentional restoration theory and stress reduction theory, which describes four characteristics of restorative environments: being away, fascination, extension, and compatibility [51]. First, “being away” refers to the extent to which an individual wants to be away from everyday life. Secondly, “fascination” means that a person views an environment as an interesting and attractive place that catches their eye. Thirdly, “extent” refers to the degree to which a sense of space is recognizable and the coherence of the elements that make up the environment has been established. Finally, “compatibility” implies that the opportunities and constraints provided by the environment are compatible with the goals and personality of the individual [52].

Peng H et al. divided the restorative environment of parks into physical and psychological environments: the physical environment includes natural and artificial environments, in which the natural and artificial environments can relieve people’s stress, while the psychological environment is used to motivate people to use the elements of the physical environment to relieve their stress [53]. In another experiment, Tan S et al. used on-site research and distributed questionnaires to break down 44 spatial elements of residents’ health needs on urban streets, and obtained 9 spatial elements that significantly affect residents’ walking trips [54]. Zhang L et al. based on the existing research, divided the community park landscape elements into three categories, namely, natural environment, rest environment, and activity environment, with a total of 11 factors, and used structural equation modeling to explore the mechanism of the influence of the landscape characteristics of urban community parks on the health perception of residents [55].

This study takes the research results of existing scholars as a theoretical reference, combines them with the status quo of the research site, and extracts these factors of the greenway from the natural environmental factors, artificial environmental factors, and psychological environmental factors (

Table 2. Three restorative environmental factors.

Name	Definition
Natural environmental factors	Natural environmental factors include air quality, plant height, plant color richness, plant seasonal/ornamental, water quality, water body ornamental, barge beauty, and natural state. Natural environmental factors are essential for the construction of greenways, and plants, water bodies, and barges are important parts of the natural environment.
Artificial environmental factors	Artificial environment factors include some artificial facilities such as landscape sketches, seats, roads, and so on; these artificial facilities are set up to meet people’s needs; these artificial facilities are often intended to meet the needs of visitors in the greenway in terms of rest, leisure, and entertainment. These sketches have a certain degree of fun and interactive features that can extend the time people stay there and increase the interest in playing again, so as to relieve stress and eliminate mental fatigue for people participating in the recreation and interaction.
Psychological environment factors	In the theory of restorative environment, there are scholars who suggest that human beings have both the desire to interact with others and the desire to be alone in life, and some studies have found that people hope that parks will be designed to be more private spaces, in which they can relax and release pressure; this theory reflects the unique requirements of human beings the environmental space.

) as the restorative environmental factors of this study (Appendix A).

2.3.2. Determination of Restorative Environmental Factors

On the basis of the preliminary construction table of the evaluation factor system, the Delphi method was used to consult the opinions of 20 experts in related professional fields as the importance judgment of secondary optimization, and the Likert scale method was used to score the preliminary selection table of greenway restorative environmental factor evaluation. The scores from 1 to 5 correspond to 5 levels of importance from low to high, “very unimportant, less important, general, more important, very important”, and then organize the scoring table of the experts to carry out the relevant calculations—the average and the plural of the evaluation factors—combined with the standard deviation and the coefficient of variation as the basis for judging the importance of the indicators (Appendix A). The higher the coefficient of variation, the greater the difference in expert opinion.

In this study, the preliminary restorative environmental factors were screened by combing the analysis of the related literature with the restorative environmental factors of parks summarized by previous researchers and the specifics of environmental factors of greenways, and then by consulting with experts and comparing the degree of importance. The average value of the factors > 3.5 was used to construct the evaluation factor system.

Finally, the evaluation factor system model (Appendix A) was constructed with three levels and eight restorative environmental factors: “Plant color richness”, “Landscape sketches richness”, “Harmonious paving”, “Appropriate road width”, “Beautiful and natural revetment”, ”High privacy space”, and “Elegant spatial forms”.

Thomas Satti’s 1–9 scale method was used to assign values to the matrix, with values 1, 3, 5, 7, and 9 indicating that two elements are equally important, slightly important, obviously important, strongly important, or extremely important compared to each other, while values 2, 4, 6, and 8 indicate that the degree of importance is in the middle of the scale. Then, 10 experts in related professional fields were invited to score, so as to obtain the scoring matrix of judgmental decision-making, which was recorded as A-B, B1-C, B2-C, and B3-C (Appendix B). Then, AHP was used to analyze the data of judgmental matrices and make consistency test (CR < 0.1), and finally obtain the results of the index weights of judgmental matrices. Based on the results of the judgment matrix, the combined weights were calculated based on the weights of the criterion and indicator layers, and then ranked to obtain the total results of the “Evaluation of Restorative Environmental Factors” (Appendix A).

2.3.3. POMS

The questionnaire for this study was the Profile of Mood States (POMS), developed by psychologists McNair et al. (1971), which is a scale of 65 adjectives used to describe emotions [56]. The scale was later simplified by Grove and Prapavessis (1992) and developed into a short-form POMS scale containing only 40 adjectives [57]. Chinese scholars (1995) simplified and revised the POMS and developed the Chinese Short-Form POMS, which is a good tool for assessing emotional states. The reliability of the Chinese POMS is 0.62–0.82, with high reliability and validity [58]. In this study, the Chinese Short-form POMS was used to quantify emotions.

2.3.4. Restorative Factor Evaluation Scale

The restorative factor rating scale is a combination of eight environmental factors scored by experts and the subjective statement “stress relief and relaxation”. Subjective scoring based on a 5-point Likert scale yielded the most significant restorative environmental factors for each of the three spatial categories in terms of subjective stress recovery.

2.3.5. Physiological Indicators Measurement Tool

Blood pressure is an important indicator of the health of the human cardiovascular system, which can reflect the sympathetic and parasympathetic activity of the human body. This study used an arm-type electronic sphygmomanometer (YE670A, Danyang, Jiangsu, China). The instrument was measured in the right upper arm by oscillometric method, the operation mode was classified as continuous operation, the results were displayed by LED digital display, the pressure measurement range was 0–300 mmHg (0–40.0 kPa), the measurement accuracy (pressure) was within ±3 mmHg (±0.4 kPa), and the pressure sensor used was a semiconductor-type pressure sensor.

2.4. Experimental Process

The experiment was selected to take place in early November 2021, and was conducted over four days, all of which were sunny, with temperatures ranging from 15 to 23 °C, consistent with human comfort temperatures, and with average daily stability and moderate variability of <10%. The same experimental time (10:00 a.m.−12:00 p.m.) was chosen for the four days of the experiment, and the two experiments were separated by one day as a way to minimize the effects due to the daily variation of the volunteers’ physiological rhythms. Thirty volunteers were randomly divided into 6 groups of 5 people each, marked by groups 1–6. On the first day, groups 1, 2, and 3 conducted experiments on the NAG, and groups 1–3 conducted the first round of experiments in the waterfront space, forested space, and lawn space in the same order; when the first round of experiments was over, they changed the space in the same order for the second round, and after the second round was over, they also carried out the third round in the same way (Figure 2). Similarly, the next day, group 4, group 5, and group 6 went to the NAG to conduct the experiment. The site staff informed the volunteers of the purpose and requirements of this experiment in advance, in order to avoid invalid experimental data.

After arriving at the experimental site, the volunteers went to each space in groups. After arriving at the designated space, the volunteers first sat quietly with their eyes closed for about 5 min, and then began to fill in the pre-test of the POMS scale, while the staff began to measure and record the physiological indicators of the volunteers before the experiment. Afterwards, the staff informed the volunteers of the range of space available for recreation, and the volunteers began to recreate in that space for 8–10 min. After the recreation, the staff measured the physiological indicators for the volunteers again and guided the volunteers to fill in the POMS scale again and evaluate the restorative environmental factors of the space (Figure 3).

2.5. Data Analysis

SPSS 21.0 software (IBM, Armonk, NY, USA) was used to analyze the physiological and psychological data of the subjects in the waterfront, underwood, and lawn spaces of the greenway by mean value analysis, Shapiro–Wilk normal distribution test, and paired samples t-test to analyze the physiological and psychological recovery effects of the volunteers in each space and compare them to explore the differences in the physiological and psychological recovery effects of the different spaces of the greenway. The evaluation table of restorative environmental factors in each space was analyzed, and the causal relationship between each restorative environmental factor and human stress release in each space was explored through mean value analysis, correlation analysis, and linear regression analysis (Figure 4).

3. Results

3.1. Normal Distribution Tests for Physiological Indicators

The three spatial sample sizes were N = 30 < 2000, so the Shapiro–Wilk normal distribution test was chosen (

Table 3. Normal distribution test for heart rate and blood pressure before and after recreation.

Space Type	Physiological Index	Before Recreation			After Recreation
		Statistics	df	Significance	Statistics	df	Significance
>Waterfront space	Heart rate	0.973	30	0.637	0.944	30	0.119
	Systolic blood pressure	0.976	30	0.705	0.967	30	0.470
	Diastolic blood pressure	0.959	30	0.296	0.976	30	0.698
>Underwood space	Heart rate	0.959	30	0.289	0.979	30	0.803
	Systolic blood pressure	0.971	30	0.562	0.968	30	0.499
	Diastolic blood pressure	0.987	30	0.966	0.951	30	0.176
Lawn space	Heart rate	0.934	30	0.064	0.978	30	0.756
	Systolic blood pressure	0.973	30	0.629	0.955	30	0.231
	Diastolic blood pressure	0.984	30	0.928	0.943	30	0.111

).

3.2. Paired t-Test for Physiological Indicators

The results are shown by the paired t-test (sample size of 30, mean ± standard deviation, * p < 0.05, ** p < 0.01). In terms of heart rate, the mean values of heart rate of the subjects in the waterfront space and the underwood space showed a significant decrease after recreation, while this significant situation did not occur in the lawn space. In terms of blood pressure, both systolic and diastolic, the mean values of blood pressure of the subjects in the three types of spaces showed a significant decrease after recreation, with the waterfront space showing the greatest decrease, with a decrease of 7.90 mmHg in systolic blood pressure and 7.60 mmHg in diastolic blood pressure (

Table 4. Paired t-tests for heart rate and blood pressure in subjects before and after recreation.

Space Type	Physiological Index	Before Recreation	After Recreation	t	p
>Waterfront space	Heart rate	73.03 ± 6.43	67.77 ± 7.80	4.90	<0.01
	Systolic blood pressure	120.97 ± 9.62	113.07 ± 10.45	6.52	<0.01
	Diastolic blood pressure	78.03 ± 4.36	70.43 ± 6.71	6.49	<0.01
>Underwood space	Heart rate	72.50 ± 6.98	68.63 ± 7.21	3.97	<0.01
	Systolic blood pressure	122.83 ± 10.45	117.57 ± 10.29	4.96	<0.01
	Diastolic blood pressure	80.43 ± 5.12	75.20 ± 5.66	6.94	<0.01
Lawn space	Heart rate	71.20 ± 7.00	69.50 ± 6.83	1.91	<0.05
	Systolic blood pressure	119.97 ± 10.90	116.00 ± 12.22	3.75	<0.01
	Diastolic blood pressure	80.47 ± 6.94	76.60 ± 6.53	4.36	>0.05

).

3.3. The Impact of Greenway Spaces on Human Physiological Health Recovery

Waterfront space and underwood space have similar and good physiological restorative effects. Both can reduce the systolic blood pressure of all subjects after the recreation. On top of this, waterfront space performs better in reducing diastolic blood pressure (29 people decreased, 1 person increased better than at the underwood space, 25 people decreased, 3 people increased, and 2 people remained unchanged). The three types of restorative performance of lawn space are not as good as those of the other two types of spaces (Figure 5).

3.4. Comprehensive Analysis of the Impact of Each Greenway Space on Human Physiological Health Recovery

Heart rate can reflect people’s tension level to a certain extent. The mean heart rate of the subjects after recreation in the three spaces of the greenway decreased by a certain amount compared with that before recreation. The average decrease in heart rate in each space was 3.61 beats/minute. It can be seen that recreation in the three different spaces of the greenway can make the human body feel relaxed and calm to a certain extent. However, compared to the lawn space, the waterfront space and the underwood space were more relaxing and calming. In terms of blood pressure, the mean systolic and diastolic blood pressures after recreation changed to a certain extent compared with those before recreation. The average decrease in systolic blood pressure and diastolic blood pressure in each space was 5.71 mmHg and 5.57 mmHg, among which the systolic blood pressure and diastolic blood pressure data before and after recreation in the waterfront space and the underwood space were significantly reduced, while the systolic blood pressure and diastolic blood pressure data in the lawn space had a certain slight decrease, which shows that the same waterfront space and the underwood space are more capable of relaxing and calming the human being (

Table 5. Mean value analysis of heart rate and blood pressure.

Space Type	Physiological Index	Before Recreation (Mean ± Sd)	After Recreation (Mean ± Sd)	Mean Difference
>Waterfront space	Heart rate	73.03 ± 6.43	67.77 ± 7.80	−5.26
	Systolic blood pressure	120.97 ± 9.62	113.07 ± 10.45	−7.90
	Diastolic blood pressure	78.03 ± 4.36	70.43 ± 6.71	−7.60
>Underwood space	Heart rate	72.50 ± 6.98	68.63 ± 7.21	−3.87
	Systolic blood pressure	122.83 ± 10.45	117.57 ± 10.29	−5.27
	Diastolic blood pressure	80.43 ± 5.12	75.20 ± 5.66	−5.23
Lawn space	Heart rate	71.20 ± 7.00	69.50 ± 6.83	−1.70
	Systolic blood pressure	119.97 ± 10.90	116.00 ± 12.22	−3.97
	Diastolic blood pressure	80.47 ± 6.94	76.60 ± 6.53	−3.87

).

3.5. Analysis of the Impact of Each Space of the Greenway on the Recovery of Human Mental Health

All three types of space in the greenway showed an increase in positive emotions and a significant decrease in negative emotions after the recreational experience. Waterfront space, underwood space, and lawn space in the greenway have certain psychological recovery effects on human beings. Compared with the lawn space, the waterfront space and the underwood space have a better effect on the psychological recovery of the human body (Figure 6).

3.6. Analysis of Greenway Restorative Environmental Factors

Reliability analysis is used to study the reliability and accuracy of completing quantitative data questionnaires. In this study, the restorative environment factor evaluation form was analyzed by using theta reliability coefficient method. The theta coefficient of the waterfront space is 0.852, the theta coefficient of the underwood space is 0.870, the theta coefficient of the lawn space is 0.868, and the theta coefficients of the restorative environment factor evaluation forms of the three spaces are greater than 0.8 in the reliability analysis, which indicates that the restorative environment factor evaluation forms of each space of the greenway are reliable and accurate.

The data on stress relief filled in by the participants after recreation in each space were analyzed by descriptive statistics. The average value of the score of “stress relief and relaxation” in each space was greater than or equal to 3.0, which indicated that the recreational behavior in each space had a restorative effect to a certain extent. The waterfront space has the highest mean score of 4.20, followed by the underwood space at 3.93 and the lawn space at 3.20. The difference in the scores of the three spaces reflects the difference in the effect of “stress relief and relaxation” on the human body after recreation in different spaces. Waterfront space is the most relaxing.

3.7. Analysis of Restorative Environmental Factors

3.7.1. Mean Value Analysis

For the waterfront space, the highest mean score was 4.03 for “Ornamental water body”, and the lowest mean score was 3.30 for “Landscape sketches richness”.

For the underwood space, the highest mean score was 4.00 for “Appropriate road width” and the lowest mean score was 3.73 for “Harmonious paving”.

For lawn spaces, “Appropriate road width” and “High privacy space” had the highest mean score of 3.70, and “Landscape sketches richness” had the lowest mean score of 3.30 (

Table 6. Mean value analysis of restorative environmental factors.

Space Type		Restorative Environmental Factors
		C1	C2	C3	C4	C5	C6	C7	C8
Waterfront space	Max	5	5	5	5	5	5	5	5
	Min	1	1	1	1	1	1	1	1
	Mean	3.50	3.30	3.60	3.77	4.03	3.53	3.47	3.69
	Sd	1.075	1.055	0.932	1.006	0.999	1.106	1.042	1.072
Underwood space	Max	5	5	5	5	5	5	5	5
	Min	2	1	1	2	1	1	2	2
	Mean	3.80	3.60	3.73	4.00	2.40	2.83	3.83	3.90
	Sd	0.887	1.070	1.015	0.830	1.037	1.085	0.986	1.029
Lawn space	Max	5	5	5	5	5	5	5	5
	Min	1	1	1	1	1	1	1	1
	Mean	3.33	3.30	3.53	3.37	3.33	3.70	3.37	3.33
	Sd	0.884	1.119	1.074	1.377	1.269	1.119	1.159	0.884

Note: Refer to Appendix A, Table A3 for the names of environmental factors C1–C8.

).

3.7.2. Correlation Analysis

For the waterfront space, the significance p values of the three restorative environmental factors, “Appropriate road width”, “Beautiful and natural revetment”, and “Elegant spatial forms”, are all less than 0.05, which indicates that these three restorative environmental factors are significantly positively correlated with stress relief and emotional recovery effects.

For the underwood space, the significance p values of the three restorative environmental factors, “Plant color richness”, “High privacy space”, and “Elegant spatial forms”, are all less than 0.05, which indicates that these three restorative environmental factors are significantly positively correlated with stress relief and emotional recovery effects.

For lawn space, the significance p values of the three restorative environmental factors, “Plant color richness”, “Ornamental water body”, and “Elegant spatial forms”, are all less than 0.05, indicating that these three restorative environmental factors are significantly positively correlated with stress relief and emotional recovery effects (

Table 7. Correlation analysis of restorative environmental factors.

Space Type		Restorative Environmental Factors
		C1	C2	C3	C4	C5	C6	C7	C8
Waterfront space	Significance P	0.657	0.362	0.798	0.009	0.874	0.015	0.939	0.020
	Pearson correlation coefficient R	0.085	−0.172	−0.049	0.467 **	0.030	0.439 *	0.015	0.429 *
Underwood space	Significance P	0.000	0.159	0.265	0.052	0.763	0.489	0.000	0.002
	Pearson correlation coefficient R	0.704 **	0.264	0.210	0.358	−0.057	0.131	0.597 **	0.538 **
Lawn space	Significance P	0.000	0.052	0.095	0.564	0.033	0.178	0.543	0.000
	Pearson correlation coefficient R	0.813 **	0.359	0.311	0.110	0.391 *	0.253	0.116	0.865 **

Note: * indicates significant correlation at p < 0.05; ** indicates significant correlation at p < 0.01.

).

3.7.3. Linear Regression Analysis

Correlation analysis is used to investigate the degree of closeness between two variables, while linear regression analysis is used to further investigate the causal relationship between variables based on correlation analysis. The above section explored the restorative environmental factors that are significantly and positively correlated with the stress relief and emotional recovery effects in each space of the greenway (

Table 8. Primary restorative environmental factors in each of the spaces.

Space Type	Primary Restorative Environmental Factors
Waterfront space	Appropriate road width
	Beautiful and natural revetment
	Elegant spatial forms
Underwood space	Plant color richness
	High-privacy space
	Elegant spatial forms
Lawn space	Plant color richness
	Ornamental water body
	Elegant spatial forms

), while linear regression analysis can further help us to explore the specific causal relationship between each restorative environmental factor and the corresponding space.

The relationship between restorative environmental factors and health recovery was examined using “stress relief and relaxation” as the dependent variable and the main restorative environmental factors in each space as the independent variables. From the results of spatial fitting degree, the environmental factors of the three types of spaces can explain the effects of stress relief and emotional recovery relatively well (

Table 9. Fitting degree of each spatial model.

Space Type	Model	R	R2	R2 after the Adjustment	Errors in Standard Estimates
Waterfront space	1	0.544 a	0.296	0.211	0.676
Underwood space	1	0.722 a	0.522	0.467	0.678
Lawn space	1	0.910 a	0.827	0.807	0.456

The letters represent the meaning of the predictor variables selected from the respective spaces.

). From the ANOVA results (p < 0.05), the existence of the regression model was significant, and at least one of the three main restorative environmental factors in each space could significantly affect the dependent variable of “stress relief and relaxation” (

Table 10. ANOVA for each space.

Space Type	Model	Square Sum	df	Mean Square	F	Significance
Waterfront space	Regression	4.796	3	1.599	3.503	0.030 b
	Residual error	11.410	25	0.456
	Total	16.207	28
Underwood space	Regression	13.032	3	4.344	9.463	0.000 b
	Residual error	11.935	26	0.459
	Total	24.967	29
Lawn space	Regression	25.949	3	8.650	41.512	0.000 b
	Residual error	5.417	26	0.208
	Total	31.367	29

The letters represent the meaning of the predictor variables selected from the respective spaces.

).

From the results of regression coefficient analysis, there are two restorative environmental factors of waterfront space, “Appropriate road width” (p = 0.013 < 0.05) and “Beautiful and natural revetment” (p = 0.027 < 0.05), that significantly influence stress relief to enable relaxation. Further, the regression coefficients of the independent variables showed that for every 1-point increase in the independent variables, the dependent variables were subsequently increased by 0.309 and 0.282 points. A restorative environmental factor in the underwood space, “Plant color richness” (p = 0.013 < 0.05), significantly influences stress relief to relaxation. Further, the regression coefficients of the independent variables showed that for every 1-point increase in the independent variables, there was a subsequent 0.666-point increase in the dependent variables. Two restorative environmental factors of lawn space, “Plant color richness” (p = 0.003 < 0.05) and “Elegant spatial forms” (p = 0.000 < 0.05), significantly affect stress relief to enable relaxation. Further, the regression coefficients of the independent variables showed that for every 1-point increase in the independent variables, the dependent variables were subsequently increased by 0.388 and 0.575 points (

Table 11. Analysis of regression coefficients for each space.

Space Type	Model	Unstandardized Coefficient		Standardization Coefficient			Collinear System
		B	Standard Error	Beta	t	Significance	Allowance	VIF
Waterfront space	(Constant)	2.636	0.540		4.883	0.000
	Appropriate road width	0.229	0.150	0.309	1.531	0.013	0.693	1.443
	Beautiful and natural revetment	0.191	0.171	0.282	1.120	0.027	0.445	2.246
	Elegant spatial forms	0.036	0.189	0.051	0.190	0.851	0.397	2.521
Underwood space	(Constant)	1.037	0.575		1.804	0.083
	Plant color richness	0.697	0.263	0.666	2.652	0.013	0.292	3.428
	High-privacy space	0.209	0.186	0.222	1.126	0.271	0.473	2.115
	Elegant spatial forms	−0.133	0.213	−0.148	−0.625	0.537	0.330	3.031
Lawn space	(Constant)	0.011	0.367		0.031	0.976
	Plant color richness	0.456	0.138	0.388	3.296	0.003	0.480	2.082
	Ornamental water body	0.050	0.068	0.061	0.730	0.472	0.953	1.049
	Elegant spatial forms	0.516	0.105	0.575	4.896	0.000	0.482	2.073

).

4. Discussion

4.1. Greenways and Human Health Recovery

This study explored the effects of greenway space on human physiological and psychological recovery through a simple outdoor experience. The experimental results show that the waterfront space is the most restorative of the three spaces, which is also consistent with other research results [59,60]. Urban river areas are important “ecological corridors” in cities that not only provide residents with coolness, but also fresh air, and these factors improve physical comfort at an objective level [61,62]. On the other hand, river water bodies have different visual and auditory effects from land surfaces, and these characteristics also have potential restorative benefits [63,64]. Further, waterfront spaces are located in areas where land and water meet and have greater biodiversity, and although this was not explicitly explored in this experiment, this may be a factor that may have a positive effect on human health recovery [65,66]. Existing studies have shown some positive correlation between restorative benefits and aesthetic preferences [67,68,69]. The richness and diversity of landscape elements in the waterfront space classified in this study may be a reason why it has the best restorative effect among the three types of space.

Underwood space had similar restorative benefits to lawn space. But in combination, the restorative benefits of the underwood space were slightly better than those of the lawn space, which may be due to the difference in the number of landscape elements. Existing research suggests that optimal restorative environments require a balance between dense vegetation and open views [70]. This is also consistent with Appleton’s theory of “refuge-prospect”, which suggests that the quality of the landscape in both the refuge and the prospect is critical to human survival [71]. The dense trees and shrubs on either side may create a refuge for visitors by creating sheltered spaces, while the scattered open lawns provide a foreground. Such environments with clear views and hiding places significantly enhance individual health recovery [72].

4.2. Restorative Environmental Factors in Different Spaces of NAG

For the waterfront space, “Appropriate road width” and “Beautiful and natural revetment” can significantly and positively influence stress relief and relaxation. For the underwood space, there is only one restorative environmental factor, “plant color richness”, which significantly affects stress recovery. On the other hand, the lawn space has the environmental factor of “Elegant spatial forms” on top of the former, which significantly affects the recovery of human health.

These environmental factors are consistent with the site environment and can also reflect the subjective views of the subjects on the recreational experience of different spaces. For the waterfront space, the appropriate width of the road and the landscape effect of the revetment determine whether visitors can approach the water body freely and safely, which undoubtedly directly determines the restoration effect of the restorative environment. As for the same green space, the underwood space and the lawn space have the same result in the environmental factor of “plant color richness”, which is in line with the spatial background of green plants as the dominant tone, and it can reflect the visitors’ requirements for the choice of colors in the plant landscape. Further, the lawn space has a more open sky view and horizontal view, which may make the visitors in the space more demanding.

4.3. Landscape Design for Greenway Spaces

For the waterfront space, landscape design should focus on revetment. Firstly, the number of trees should be reduced so that visitors can easily satisfy their hydrophilicity from the open view and close contact. The second is to improve the aesthetics of the plants along the waterfront, which can be achieved by increasing the number of aquatic flowering plants and replacing unnatural elements with natural ones. The width of the road should be determined to ensure the safety of visitors in the process of recreation and allow for visitors to have a good water experience.

For the underwood space, it should pay attention to the natural plant mix for space optimization design. The plant community is dominated by green plants and matched with other colored plants, and both sides of the greenway are dominated by tall arbor with part of the shrubs and lawns, which can create shade and diversified landscape levels of the greenway and provide a peaceful and comfortable environment for visitors to play. The greenway is divided into two parts, the walking path and the cycling path, so that visitors of different types of activities cannot disturb each other.

For the lawn space, it should ensure the natural characteristics of good lawn cover and plant species diversity in order to use the visual characteristics and texture of plants to achieve the lawn space to human physiological and psychological perception of recovery, which can be replaced by the natural configuration of plants to the rules of the arrangement.

4.4. Limitation and Future Study

The results of this study have practical implications for the exploration and spatial design of restorative benefits of urban greenways. However, there are some limitations to this study. Firstly, this study focused on experiments in autumn, but the restorative benefits may differ in other seasons, so the results of experiments in other seasons are yet to be refined [73,74]. The subjects in this study were all college students. Although this part of the population has higher comprehensive quality and broader knowledge, which is more conducive to the convening and smooth implementation of the experiment [75], the population of greenway users is not completely covered, and people of different ages, occupations, education, and even economic status should be included in the process of future research [76]. Although the number of subjects (n = 30) tends to be normally distributed at the level of mathematical statistics, more subjects are still needed as experience samples in the future [77,78]. In addition, jogging and cycling are also important forms of exercise for outdoor excursions [79,80,81,82] that were overlooked in this study and need to be added in future experiments. This study did not explore the effects of interactions between different factors on restorative benefits [83,84,85], which need to be noted in future experiments. Finally, landscape experience experiments are usually subjective and qualitative experiences of visitors. However, quantitative research is also the future direction of the landscape discipline. Therefore, specific design criteria for environmental features that influence restoration need to be identified in future studies [86,87] (optimal visual greening index [88,89], greenway path width [90], distance from major landscape elements [91], number of landscape facilities [92], etc.), which would not only enrich the quantitative data, but also enhance the persuasiveness and scientific validity of the experimental results.

5. Conclusions

Restorative environments have been a hot topic of research in the discipline of landscape ecology, but there are not many research studies exploring the restorative benefits of different spaces in riverside greenways. In this paper, three types of typical spaces were classified according to the current situation of the study site, and the differences and variations of restorative benefits and restorative environmental factors among the spaces were explored. The waterfront space had the best restorative benefits, and the width of the road and the degree of naturalness of the barge significantly affected the stress relief and relaxation of visitors in the waterfront space. The restorative benefits of the underwood space were slightly better than those of the lawn space, and the richness of plant colors significantly influenced the restorative effects of visitors in both spaces. Elegant spatial form was another important restorative attribute of the lawn space. This study suggest that in the design and planning of urban greenways, the selection of landscape elements and plant configurations should be tailored to different types of spaces to ensure maximum public recreational and restorative experiences. By exploring the positive impacts of urban greenway environments on physical and mental health, this study provides nature-based solutions for achieving quality urbanization.