1 Domagoj Tomičić
2 Benjamin Osmančević
3 Kata Ivanišević
1 Teaching Institute of Emergency Medicine of the Istria County, Pula, Croatia
2 Juraj Dobrila University of Pula, Faculty of Medicine, Pula, Croatia
3 University of Rijeka, Faculty of Health Studies, Rijeka, Croatia
https://doi.org/10.24141/2/9/2/7
Author for correspondence:
Domagoj Tomičić
Teaching Institute of Emergency Medicine of the Istria County Pula, Croatia
E-mail: domagoj.tomicic0304@gmail.com
Keywords: emergency medical services, cardiopulmonary resuscitation, physical activity
Results. A statistically significant positive corre- lation was found between physical activity level and the quality of chest compressions (p<0.001). Participants with higher physical activity levels achieved better results in overall compression qual- ity (p=0.001), compression depth (p=0.009), and frequency (p=0.003). No statistically significant dif- ferences were found for chest recoil (p=0.470). Gen- der had no significant effect on overall compression quality, depth, or frequency; however, female partici-
pants achieved significantly better results in chest recoil (p=0.034).
Cardiopulmonary resuscitation (CPR) is a vital proce- dure for survival in individuals experiencing cardiac arrest. According to the Resuscitation Council UK,
reported a significant decline in compression quality after just a few minutes of CPR, with effectiveness decreasing to only 28% after five minutes (5). These findings highlight the relevance of physical prepared- ness in sustaining CPR performance.
While some authors have explored gender-related differences in CPR performance, results remain in- conclusive. For example, Ochoa et al. (1998) found no significant differences between male and female participants in overall CPR quality, suggesting that gender alone may not be a decisive factor (6).
Although the relationship between physical activ- ity and CPR performance has been increasingly ad- dressed in international research, no such studies have, to our knowledge, been conducted in the Re- public of Croatia. This highlights the need for locally relevant data on this topic.
the annual incidence of out-of-hospital cardiac ar-
rest (OHCA) is approximately 55 cases per 100,000
population, with a survival rate to hospital discharge of around 9% (1). Globally, the average incidence of OHCA in adults is similar, yet the overall survival rate remains low, with an average of just 7% (2). In such critical situations, timely and high-quality CPR is es- sential to maintain blood flow and oxygen supply to vital organs until emergency medical services arrive or more advanced interventions can be applied.
The basic components of CPR include chest com- pressions and artificial respiration. The quality of these measures is closely associated with resuscita- tion outcomes. The European Resuscitation Council guidelines recommend a compression rate of 100– 120 compressions per minute and a depth of 5–6 cm, with full chest recoil between compressions (3). Performing CPR in accordance with these guidelines requires not only proper technique but also consid- erable physical strength and endurance—particularly during prolonged efforts.
Previous studies have suggested that the physical fit- ness of emergency medical service (EMS) personnel may be associated with their ability to maintain high- quality chest compressions over time. Nayak et al. (2020) observed that individuals with higher levels of physical activity maintained compression quality more consistently, while less active individuals showed signs of fatigue earlier (4). Similarly, Ock et al. (2011)
The aim of this study was to examine the relationship between the level of physical activity and the quality of chest compressions during cardiopulmonary resus- citation among emergency medical service personnel, while also considering potential gender differences.
The study was designed as a cross-sectional study. A total of 34 employees from the out-of-hospital emer- gency medical service participated in the research. Inclusion criteria allowed for participants aged be- tween 18 and 65 years; however, the final sample included individuals aged between 20 and 62 years. The average age of participants was 38.4 years (SD=11.6), and the average length of work experi- ence in emergency medical services was 11.2 years (SD=7.9). The sample included professionals from various occupational backgrounds, including nurses (n=18), drivers (n=10), and physicians (n=6).
Participation was voluntary, and informed consent was obtained from all participants prior to inclusion. The study was conducted between June 1 and July 18, 2024. The researcher was present during individ- ual data collection to provide standardized instruc- tions and technical support. While the researcher had access to participants’ performance during testing, no documents or records linking individual identities to performance data were retained. The final data- set contained only anonymized identification codes (“Participant N”), ensuring confidentiality.
All participants had completed formal cardiopulmo- nary resuscitation training in accordance with na- tional regulations (Official Gazette No. 12/2025), which is a mandatory requirement for working in the emergency medical service. Given their professional roles and years of experience, all participants had previously encountered CPR situations in real-life emergency settings.
Data were collected in two phases. In the first phase, participants completed a structured socio-demo- graphic questionnaire developed for the study, which included questions on age, gender, height, weight, occupation, and years of work experience. They also completed the International Physical Activity Ques- tionnaire (IPAQ – long version, 2006), validated in
Approval for the study was obtained from the Ethics Committee of the Teaching Institute of Emergency Medicine of Istria County (Ref. No.: 2163-5-1-336/24). The study was conducted according to ethical princi- ples while maintaining the anonymity of the partici- pants. All participants provided a written consent for the use of the data collected via questionnaires exclu- sively for the purposes of this research.
The collected data was analyzed using IBM SPSS Statistics software, version 22. The normality of the distribution of the continuous variables was tested using the Kolmogorov-Smirnov test and the Shapiro- Wilk test, both of which showed significant devia- tions from a normal distribution. The data were then analyzed using descriptive statistics, the Kruskal- Wallis test and the chi-square test (χ²). A linear mixed model (LMM) was used to assess the impact of physi- cal activity level on the quality of chest compres- sions across the measurement intervals. The results were interpreted using F-values and p-values, with the significance level set at p<0.05.
Croatian by Pedišić et al. (2011) (7). This instrument categorized participants into low, moderate, or high
physical activity levels; however, for the purposes of statistical analysis, raw IPAQ scores (MET-minutes/ week) were used to preserve accuracy.
In the second phase, participants performed an eight- minute CPR session on a simulation manikin (Resusci Anne QCPR, Laerdal Medical, Stavanger, Norway) connected to the Laerdal QCPR application (version 6.2.10). This system enabled automated measure- ment of chest compression parameters, including depth (in millimeters), rate (compressions per minute), proper chest recoil (percentage), and overall CPR per- formance (percentage). Participants could stop the simulation at any point if they experienced fatigue or were unable to continue. Prior to testing, all partici- pants received standardized instructions based on the European Resuscitation Council guidelines.
Descriptive statistics included a categorization of CPR performance into three levels—Basic ability (0–49%), In- termediate ability (50–74%), and Advanced ability (75– 100%). However, all inferential statistical analyses were conducted using continuous (raw) performance scores to maintain measurement precision and sensitivity.
A total of 34 emergency medical service personnel participated in the study. Of these, 19 were male (55.9%) and 15 female (44.1%). Participants were categorized into three levels of physical activity based on IPAQ: low (n=10; 29.4%), moderate (n=12; 35.3%), and high (n=12; 35.3%) (Table 1).
Table 1. Distribution of participants by gender and physical activity level | ||||
Gender | Low activity | Moderate activity | High activity | Total |
Male | 6 | 6 | 7 | 19 |
Female | 4 | 6 | 5 | 15 |
Total | 10 | 12 | 12 | 34 |
Note: There is no statistically significant difference in gender distribution across physical activity levels (χ²=0.476, p=0.788). | ||||
The Linear Mixed Model (LMM) analysis showed a statistically significant positive relationship between physical activity level (measured continuously using total MET-minutes/week) and chest compression quality over time (F=1272.954; p<0.001). Estimates indicated that compression quality improved steadily across the four 2-minute intervals, with the increase plateauing slightly between the third and fourth in- terval (Table 2).
Table 2. Estimates from the Linear Mixed Model (LMM) for chest compression quality | ||||
Time Interval | Estimate | Standard Error | t-value | p-value |
1st | 0.507 | 0.124 | 4.09 | <0.001 |
2nd | 0.606 | 0.147 | 4.12 | <0.001 |
3rd | 0.687 | 0.168 | 4.09 | <0.001 |
4th | 0.693 | 0.169 | 4.10 | <0.001 |
Note: Estimates reflect progressive improvement in compression quality across time intervals. The trend stabilizes from the third interval onward. | ||||
To improve interpretability, estimated marginal means (EMMs) were calculated for each activity level at each time point (Table 2a). These values show how performance varied across groups.
Table 2a. Estimated marginal means for compression quality by activity level | |||
Time Interval | Low Activity | Moderate Activity | High Activity |
1st | 45.7 | 62.1 | 78.4 |
2nd | 47.3 | 64.9 | 82.0 |
3rd | 49.2 | 66.8 | 84.2 |
4th | 49.0 | 67.1 | 84.5 |
Note: High activity participants maintained consistently higher predicted CPR quality across all time points. | |||
The Kruskal-Wallis test indicated significant differ- ences in chest compression quality between physical activity groups at all time intervals. Mann-Whitney post-hoc tests identified pairwise differences, es-
pecially between low and high activity participants, and to a lesser extent between moderate and high groups (Table 3).
Overall CPR quality was calculated as the arithmetic mean across all four time intervals. Kruskal-Wallis and Mann-Whitney tests showed significant differences between groups in quality, depth, and frequency, but not in chest recoil (Table 4).
Spearman’s correlation analysis confirmed a strong and statistically significant positive relationship be- tween overall physical activity level, measured in MET-minutes per week, and average chest compres- sion quality (ρ=0.79, p<0.001). This result suggests that individuals with higher levels of physical activity tend to perform higher-quality chest compressions during CPR.
While gender did not significantly affect overall CPR quality, depth, or frequency, a statistically significant difference was found for chest recoil, where female participants performed better (Table 5).
The results of this study indicate a statistically sig- nificant positive association between physical ac- tivity level and the quality of chest compressions during cardiopulmonary resuscitation (p<0.001). Participants with higher activity levels generally maintained better compression quality throughout the eight-minute simulation, while those with lower activity levels showed a more noticeable decline in performance after the first minute. This pattern is reflected in the estimated marginal means (EMMs), which increased steadily until the third interval and
Table 3. Kruskal-Wallis and Mann-Whitney post-hoc tests for time intervals | ||||||
Time | Group Comparison | Median (Low–Mod–High) | Mean Rank | χ² (KW) | p (KW) | U (MW) p (MW) |
1st | Low – Moderate Moderate – High | 46.0 – 66.5 – 81.0 | 9.70–18.00–23.50 | 14.71 | <0.001 | 24.5 0.007 37.0 0.036 |
23.0 | 0.005 |
36.5 | 0.030 |
36.5 | 0.046 |
30.0 | 0.021 |
42.0 | 0.068 |
28.0 | 0.018 |
2nd Low – Moderate 43.0 – 68.0 – 83.0 Moderate – High | 9.55–17.63–24.00 | 15.30 | <0.001 |
3rd Low – Moderate 48.0 – 70.5 – 85.0 Moderate – High | 11.35–16.29–23.83 | 10.48 | 0.005 |
4th Low – Moderate 50.0 – 71.0 – 84.0 | 12.40–15.92–23.33 | 8.53 | 0.014 |
Moderate – High
Note: Significant differences were observed between most group pairs. Differences between low and moderate in the fourth interval approached significance (p=0.068).
Table 4. Group comparison of performance parameters (with medians and post-hoc tests) | |||||
Parameter | Median (L–M–H) | Mean Rank (L–M–H) | χ² | p (KW) | Significant Comparisons (MW) |
Chest compression quality | 44.5 – 62.0 – 82.0 | 10.2 – 16.58 – 24.50 | 14.63 | <0.001 | Low–Mod (p=0.011), Mod–High (p=0.041) |
Compression depth | 51.0 – 64.0 – 73.5 | 12.3 – 16.83 – 22.50 | 9.31 | 0.009 | Low–High (p=0.014) |
Compression frequency | 42.5 – 67.0 – 74.0 | 10.4 – 18.33 – 22.58 | 11.70 | 0.003 | Low–Mod (p=0.019), Mod–High (p=0.047) |
Chest recoil | 66.5 – 65.0 – 68.0 | 17.0 – 15.58 – 19.83 | 1.51 | 0.470 | None |
Note: The high physical activity group outperformed others in all parameters except chest recoil, which did not significantly differ between groups. | |||||
Table 5. Chest compression performance by gender | |||||
Parameters | Gender | Below Average (%) | Above Average (%) | Chi-square test (χ²) | p |
Compression | Female | 40.0 | 60.0 | 1.449 | 0.229 |
depth | Male | 21.05 | 78.95 | ||
Note: Above/below average classification based on median split. Only chest recoil showed a statistically significant gender difference in favor of female participants.
0.034
4.480
73.33
36.84
26.67
63.16
Female
Male
Chest recoil
Compression frequency
Female 40.0 60.0
0.035 0.851
Male 36.84 63.16
then plateaued, with the highest predicted values consistently observed in the high activity group across all time points. In contrast, the low activity group consistently displayed lower mean ranks and median values across all intervals.
Post-hoc comparisons further revealed that differ- ences in compression quality were statistically sig- nificant between physical activity groups at nearly all intervals. The strongest differences were observed
between the low and high activity groups, with some significant differences also found between moderate and high activity participants. These results support the idea that higher physical activity levels are as- sociated with the ability to maintain higher compres- sion quality over time.
These findings are in line with current recommenda- tions suggesting frequent rotation of team members performing compressions to minimize fatigue and
help maintain CPR quality (8). Similar observations were reported by Nayak et al. (4), while Ippolito et al.
(9) did not find significant differences in overall CPR quality by activity level but did observe variation in compression depth. This suggests that certain CPR components may be more closely related to physical fitness than others.
Our findings also correspond with the results of Oer- mann et al. (10), who reported that nursing students with higher physical activity levels achieved better compression rate and depth during simulations. Like- wise, Krarup et al. (11) found that professional EMS teams involved in regular physical conditioning per- formed CPR at higher quality levels than volunteers without such training. These results indicate that physical activity may be associated with improved CPR performance, even in non-professional settings.
Additional insights come from McDonald et al. (12), who showed that individuals with greater muscle mass and higher BMI were more likely to achieve adequate compression depth, regardless of gender. In our study, gender did not have a statistically significant effect on compression depth or frequency. Interestingly, female participants performed significantly better in chest recoil (p=0.034). This finding was consistent across intervals and was statistically significant when data were aggregated. This may reflect greater precision or control among female participants, as proper chest recoil requires full release of pressure between com- pressions—an action that is likely more dependent on technique than physical strength.
These findings are consistent with previous research by Ochoa et al. and Jaafar et al. (6,13), which sug- gests that women may demonstrate greater accu- racy in certain CPR components. When controlling for variables such as BMI and physical fitness, gender alone does not appear to be a major factor influenc- ing overall CPR quality (14,15).
Vaillancourt and Stiell (16) similarly highlighted the relevance of physical preparedness, noting that lay responders with lower fitness levels experienced a noticeable decline in CPR performance within the first few minutes. Ahn et al. (17) emphasized the importance of team coordination and structured task rotation, showing that planned switching of roles can help maintain compression quality—even among physically fit responders.
The practical implications of these findings point to the potential benefits of training programs that in-
clude physical conditioning components, particularly those targeting endurance and upper body control. Structured rotation protocols—particularly during prolonged resuscitation—may help compensate for fatigue-related declines in performance, especially among less physically active responders. While the design of this study does not allow for conclusions about causality, the observed associations support the relevance of physical fitness in CPR-related per- formance.
Despite the significance of the findings, several limi- tations must be acknowledged. The sample size was relatively small (N=34), which may limit the gener- alizability of results. Physical activity levels were assessed via the self-reported IPAQ questionnaire, which may introduce response bias. Additionally, oth- er potentially important variables—such as age, BMI, and prior CPR experience—were not included in the analysis. Finally, while manikin-based simulations of- fer controlled environments for measuring CPR qual- ity, they do not fully replicate the stress and variabil- ity of real-life cardiac arrest situations.
Future studies should involve larger, more diverse samples and incorporate objective fitness metrics. Research should also examine the role of age and body composition, as well as the combined effects of fatigue, stress, and environmental conditions on CPR performance. Longitudinal designs could provide insight into the long-term impact of physical training on resuscitation outcomes.
Overall, these results align with a growing body of evidence associating physical activity with CPR qual- ity. They highlight the importance of physical prepar- edness among EMS personnel and suggest that com- bining physical and technical training components may help improve the quality of resuscitation efforts in both professional and lay responder settings.
The results of this study show that a high level of physical activity significantly improves the quality of chest compressions during cardiopulmonary resusci- tation. Participants with a high level of physical ac- tivity were able to maintain the quality of compres- sions over a longer period, while participants with a lower level of activity experienced a more rapid decline in performance. These results underline the importance of the physical fitness among emergency medical service personnel in ensuring the effective- ness of CPR, especially during prolonged resuscita- tion efforts.
Although gender was not a determining factor in the overall quality of chest compressions, differences were observed in certain parameters such as chest recoil, where women performed better.
Conceptualization and methodology (DT, BO, KI); Data curation and formal analysis (DT, KI); Investigation and project administration (DT); and Writing – original draft and review & editing (DT, BO, KI). All authors have approved the final manuscript.
The authors declare no conflicts of interest.
Not applicable.
This research did not receive any specific grant from funding agencies in the public, commercial, or not- for-profit sectors.
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