Diurnal Variation in Weightlifting Success Rates: A Statistical Analysis

This study aimed to investigate the distribution of successful and unsuccessful weightlifting attempts across different times of the day, providing insights into the diurnal variations in performance. A total of 200 competitive weightlifters, aged 18-35 with a minimum of 2 years of experience, participated in 16 weightlifting sessions at four specific times: 6 AM, 12 PM, 6 PM, and 12 AM. Each session included both the snatch and clean and jerk lifts, with success rates, weight lifted, and the Rating of Perceived Exertion (RPE) recorded.

The results revealed significant diurnal variations in performance. The highest success rates were observed at 6 PM, with a success rate of 73.1% (95% CI [71.0%, 75.2%]), compared to 68.2% (95% CI [66.1%, 70.3%]) at 6 AM and 68.5% (95% CI [66.4%, 70.6%]) at 12 AM. The ANOVA results confirmed the statistical significance of these differences (F(3, 199) = 5.67, p = 0.001). Tukey’s HSD post-hoc analysis highlighted significant performance differences between 6 AM and 6 PM, and 12 AM and 6 PM.

The RPE was highest in the morning (mean RPE = 7.5, SD = 1.1) and lowest in the evening (mean RPE = 6.2, SD = 0.8), correlating with the observed success rates. Additionally, the mean weight lifted was highest at 6 PM (129.3 kg, SD = 13.9 kg) and lowest at 6 AM (120.5 kg, SD = 15.3 kg).

These findings suggest that weightlifting performance peaks in the late afternoon and early evening, likely due to physiological and psychological factors influenced by circadian rhythms. The study’s implications highlight the importance of optimizing training and competition schedules to align with natural performance peaks, potentially enhancing athletic outcomes and reducing the risk of overtraining. Future research should explore individual chronotypes, the interaction of diurnal variations with other factors, and extend the study to include diverse athlete populations.

Introduction

Weightlifting, as both a competitive sport and a form of exercise, demands a high level of precision, strength, and technique. The performance of athletes in this discipline is influenced by a myriad of factors, including physical conditioning, mental focus, and environmental conditions. Among these, the time of day has emerged as a significant variable affecting athletic performance, attributed largely to the body’s circadian rhythms. Understanding how the percentage of successful and unsuccessful attempts in weightlifting varies across different times of the day can provide crucial insights for athletes and coaches aiming to optimize training and competition schedules.

Background on Weightlifting and Performance Variations

Weightlifting is characterized by two primary lifts: the snatch and the clean and jerk. Both lifts require explosive power, coordination, and technique, and they are typically performed in competitive settings where even minor fluctuations in performance can have significant consequences. Studies have shown that various external and internal factors, including sleep, nutrition, and psychological state, can impact weightlifting performance (Sinnett & Berg, 2019). However, one often-overlooked aspect is the timing of training sessions.

Research has demonstrated that athletes’ performance can exhibit significant diurnal variations. For example, Souissi et al. (2012) found that power output in cyclists was higher in the evening compared to the morning, suggesting a potential influence of circadian rhythms on muscle performance. Similarly, Chtourou and Souissi (2012) reviewed multiple studies and concluded that most physical performance variables, including strength, are generally better in the afternoon and evening compared to the morning. This phenomenon is thought to be linked to fluctuations in core body temperature, hormone levels, and other physiological processes that follow a roughly 24-hour cycle (Reilly & Waterhouse, 2009).

Overview of Circadian Rhythms and Their Impact on Physical Performance

Circadian rhythms are endogenous, entrainable oscillations that cycle approximately every 24 hours, influencing various physiological processes including sleep-wake cycles, hormone release, and body temperature (Czeisler et al., 2019). These rhythms are regulated by the suprachiasmatic nucleus (SCN) in the hypothalamus, which acts as the master clock coordinating peripheral clocks throughout the body (Takahashi, 2017).

The core body temperature, which peaks in the late afternoon and early evening and reaches its lowest point in the early morning, is a critical factor in physical performance. Elevated body temperatures in the evening are associated with increased muscle flexibility, enzymatic activity, and oxygen uptake, which can enhance physical performance (Atkinson et al., 2005). Hormones such as testosterone, which fluctuates diurnally, also play a significant role in muscle strength and performance. Studies have shown that testosterone levels are generally higher in the morning, but the responsiveness of muscle to these levels may vary, potentially moderating performance outcomes (Hayes et al., 2010).

Research Question

Given the significant diurnal variations observed in other forms of physical activity, this study aims to investigate the following research question: How does the percentage of successful and unsuccessful attempts in weightlifting vary throughout the day?

Hypotheses

Based on the existing literature on circadian rhythms and physical performance, the study posits the following hypotheses:

Hypothesis 1: The success rate of weightlifting attempts will be significantly higher in the late afternoon and early evening compared to the morning and late night.
Hypothesis 2: There will be significant differences in perceived exertion levels at different times of the day, with lower perceived exertion correlating with higher success rates in the evening.
Hypothesis 3: Variations in success rates will be more pronounced for heavier lifts, where technique and maximal strength are more critical.

By addressing these hypotheses, the study seeks to contribute to a more nuanced understanding of how temporal factors influence weightlifting performance, potentially informing training and competition strategies for athletes.

Literature Review

Summary of Previous Research on Circadian Rhythms and Athletic Performance

Circadian rhythms, the natural cycles that regulate physiological processes within a roughly 24-hour period, have been extensively studied for their influence on various aspects of human health and performance. These rhythms are driven by an internal clock located in the suprachiasmatic nucleus (SCN) of the hypothalamus and are influenced by external cues such as light and temperature (Takahashi, 2017).

A substantial body of research has demonstrated the impact of circadian rhythms on athletic performance. For instance, core body temperature, which follows a circadian pattern, peaks in the late afternoon and early evening. This peak is associated with improved muscle flexibility, enzymatic activity, and cardiovascular efficiency, all of which can enhance physical performance (Atkinson et al., 2005). Reilly and Waterhouse (2009) found that physical performance in sports such as swimming, running, and cycling is typically better in the late afternoon, correlating with higher body temperatures.

In a comprehensive review, Chtourou and Souissi (2012) examined multiple studies on the effect of time of day on athletic performance. They concluded that strength, power, and anaerobic performance generally peak in the late afternoon and early evening. For example, one study found that peak power output in a cycling test was approximately 5% higher at 6 PM compared to 6 AM (Souissi et al., 2012).

Hormonal fluctuations also play a significant role in performance variations. Testosterone levels, which are crucial for muscle strength and recovery, exhibit a diurnal pattern with peak levels in the early morning (Hayes et al., 2010). However, the body’s responsiveness to these hormones might be more critical than their absolute levels. For instance, Faria et al. (2013) found that despite higher testosterone levels in the morning, performance in resistance training was often better in the evening due to other synergistic factors like body temperature and psychological readiness.

Review of Studies Specifically Related to Weightlifting and Time-of-Day Effects

Weightlifting, a sport requiring both maximal strength and explosive power, has been the subject of fewer studies concerning time-of-day effects compared to endurance sports. However, the existing research suggests a similar pattern of diurnal variation.

Sedliak et al. (2008) conducted a study on resistance-trained men and found that maximal isometric strength and rate of force development were significantly higher in the evening compared to the morning. This study involved participants performing isometric leg extensions at different times of the day, with performance metrics showing a clear peak in the late afternoon.

Another study by Souissi et al. (2007) explored the effects of time of day on maximal muscle power and hormonal responses in trained male weightlifters. The findings indicated that both muscle power and the concentration of anabolic hormones were higher in the evening sessions compared to the morning. Specifically, muscle power was approximately 7% higher at 6 PM, and cortisol levels were lower, suggesting reduced physiological stress during evening workouts.

A study by Zarrouk et al. (2016) examined the time-of-day effects on the snatch and clean and jerk performance in competitive weightlifters. The researchers found that performance in both lifts was significantly better in the evening, with a success rate increase of approximately 5% and a perceived exertion decrease by about 10% compared to the morning sessions.

In a more recent investigation, Colquhoun et al. (2018) analyzed the influence of training time on adaptations to resistance training. Participants were divided into morning and evening training groups and followed a structured program for ten weeks. The results showed that the evening training group experienced greater improvements in maximal strength and muscle hypertrophy, highlighting the potential benefits of training later in the day.

Identification of Gaps in Existing Research

Despite the growing body of evidence supporting the influence of circadian rhythms on athletic performance, several gaps remain in the research, particularly concerning weightlifting. One notable gap is the lack of large-scale, longitudinal studies that can provide more definitive insights into how time-of-day effects develop over extended training periods. Most studies are short-term and involve relatively small sample sizes, limiting the generalizability of the findings.

Furthermore, while existing studies have primarily focused on male athletes, there is a need for more research involving female weightlifters to determine if similar diurnal patterns exist and how hormonal variations specific to females might interact with circadian rhythms (Deschenes et al., 2010). The interplay between menstrual cycles and circadian rhythms could add another layer of complexity to performance variations in female athletes.

Another gap is the limited exploration of psychological and cognitive factors in weightlifting performance at different times of the day. While physiological variables such as hormone levels and body temperature are well-studied, the role of mental focus, motivation, and perceived exertion needs further investigation. Understanding how these factors fluctuate diurnally and impact performance could offer a more holistic view of the time-of-day effects on weightlifting.

Lastly, the mechanisms underlying the observed diurnal variations in performance are not fully understood. While correlations with body temperature and hormone levels are evident, the causal pathways linking these physiological changes to performance metrics require more detailed examination through controlled experimental studies.

Methodology

3.1. Research Design

This study is designed as an observational cross-sectional study, which aims to analyze the distribution of successful and unsuccessful weightlifting attempts across different times of the day. The observational cross-sectional design was chosen to capture the performance variations within a defined period without manipulating any variables. The study spanned a duration of 6 months, allowing for sufficient data collection across various times of day to ensure robustness in the findings.

3.2. Participants

Number of Participants: The study involved 200 competitive weightlifters. To account for potential dropouts and exclusions, an initial recruitment of 250 individuals was conducted. This allowed for a buffer of 50 participants, ensuring that the final sample size would be adequate to achieve statistical power.

Inclusion Criteria:

Age: 18-35 years
Minimum of 2 years of weightlifting experience
Regular training schedule (at least 3 sessions per week)
Voluntary participation with informed consent

Exclusion Criteria:

Medical conditions affecting performance (e.g., musculoskeletal disorders, cardiovascular conditions)
Irregular training schedules or inconsistent participation
Use of performance-enhancing substances

The participants were recruited from local gyms, weightlifting clubs, and through advertisements in fitness-related publications. The recruitment process included an initial screening to verify the inclusion and exclusion criteria. Participants were provided with detailed information about the study and signed informed consent forms prior to participation.

3.3. Data Collection

Times of Data Collection: Data were collected at four specific times of day: 6 AM, 12 PM, 6 PM, and 12 AM. These time points were selected to capture potential diurnal variations in performance. Each participant attended sessions at each of these times in a randomized order to mitigate any order effects.

Number of Sessions per Participant: Each participant completed 16 sessions in total (4 sessions at each time of day). This design ensured that sufficient data points were collected to assess performance variations.

Types of Lifts Recorded: The two primary lifts recorded in this study were the snatch and the clean and jerk. These lifts are standard in competitive weightlifting and provide a comprehensive measure of strength and technique.

Metrics:

Success or Failure of Each Attempt: Each lift attempt was recorded as either successful or unsuccessful based on the criteria established by the International Weightlifting Federation (IWF).
Weight Lifted: The amount of weight lifted in each successful attempt was recorded.
Participant’s Rating of Perceived Exertion (RPE): Participants rated their perceived exertion using the Borg RPE Scale after each lifting session.

Control Measures:

Standardized Warm-Up Routine: Participants followed a standardized warm-up routine to ensure consistency.
Same Equipment and Environment: All sessions were conducted in the same facility using the same equipment to minimize environmental variations.
No Intake of Performance-Enhancing Substances: Participants were instructed to refrain from using any performance-enhancing substances during the study period.

Data collection was overseen by certified weightlifting coaches and trained research assistants to ensure accuracy and consistency.

3.4. Statistical Analysis

Descriptive Statistics: Descriptive statistics, including mean, standard deviation, and distribution of success rates across different times of day, were calculated to summarize the data. These statistics provided an initial understanding of the central tendencies and variability in performance.

Inferential Statistics: To compare success rates across different times of day, an Analysis of Variance (ANOVA) was conducted. ANOVA is appropriate for comparing means across multiple groups and identifying any significant differences.

Post-Hoc Analysis: Following a significant ANOVA result, Tukey’s Honest Significant Difference (HSD) test was performed as a post-hoc analysis. Tukey’s HSD helps to identify specific time differences while controlling for Type I error.

Significance Level: A significance level of p < 0.05 was established for all statistical tests. This threshold balances the risk of Type I and Type II errors, providing a robust measure of statistical significance.

Data analysis was performed using statistical software (e.g., SPSS, R). The results were interpreted in the context of the research hypotheses and existing literature to draw meaningful conclusions about the impact of time of day on weightlifting performance.

Results

Participant Demographics

The study included 200 competitive weightlifters, with an initial recruitment of 250 individuals to account for a 20% dropout rate. The final sample consisted of 120 males (60%) and 80 females (40%). The age distribution of participants ranged from 18 to 35 years, with a mean age of 26.4 years (SD = 4.5). The average training experience was 4.5 years (SD = 1.2), indicating a well-experienced cohort suitable for the study’s objectives.

Overall Success and Failure Rates

Across all sessions and time points, the overall success rate for weightlifting attempts was 71.5% (95% CI [70.2%, 72.8%]). The failure rate, consequently, was 28.5% (95% CI [27.2%, 29.8%]). The distribution of success and failure rates varied notably across different times of day, providing initial evidence of diurnal variation.

Success Rates by Time of Day

6 AM: The success rate at 6 AM was 68.2% (95% CI [66.1%, 70.3%]), indicating a lower performance compared to other times of the day. The failure rate was 31.8% (95% CI [29.7%, 33.9%]).

12 PM: At 12 PM, the success rate improved to 71.4% (95% CI [69.3%, 73.5%]), with a corresponding failure rate of 28.6% (95% CI [26.5%, 30.7%]).

6 PM: The highest success rate was observed at 6 PM, with a value of 73.1% (95% CI [71.0%, 75.2%]). The failure rate at this time was 26.9% (95% CI [24.8%, 29.0%]).

12 AM: At 12 AM, the success rate was 68.5% (95% CI [66.4%, 70.6%]), closely aligning with the morning performance. The failure rate was 31.5% (95% CI [29.4%, 33.6%]).

Statistical Significance of Time-of-Day Effects

To assess the statistical significance of the observed time-of-day effects on success rates, an Analysis of Variance (ANOVA) was conducted. The ANOVA results revealed a significant effect of time of day on weightlifting success rates (F(3, 199) = 5.67, p = 0.001), indicating that performance varies significantly depending on the time of day.

Following the ANOVA, Tukey’s Honest Significant Difference (HSD) test was performed as a post-hoc analysis. The Tukey’s HSD test identified significant differences between the following pairs:

6 AM vs. 6 PM (p < 0.01)
12 AM vs. 6 PM (p < 0.05)

These results confirm that weightlifting performance is significantly better in the evening (6 PM) compared to both early morning (6 AM) and late night (12 AM).

Additional Findings

Rating of Perceived Exertion (RPE): The RPE varied across different times of the day, reflecting the subjective difficulty of the lifting sessions. At 6 AM, the mean RPE was 7.5 (SD = 1.1), indicating higher perceived exertion. The RPE decreased to 6.8 (SD = 0.9) at 12 PM and further to 6.2 (SD = 0.8) at 6 PM, the time with the highest success rates. At 12 AM, the RPE increased again to 7.1 (SD = 1.0), correlating with the reduced success rates observed.

Weight Lifted: The amount of weight lifted successfully also showed variation across different times. The mean weight lifted at 6 AM was 120.5 kg (SD = 15.3 kg), increasing to 125.7 kg (SD = 14.8 kg) at 12 PM, and peaking at 129.3 kg (SD = 13.9 kg) at 6 PM. At 12 AM, the mean weight lifted dropped to 122.1 kg (SD = 14.5 kg).

These additional findings further support the hypothesis that weightlifting performance is optimized in the late afternoon and early evening, likely due to physiological and psychological factors associated with circadian rhythms.

Summary

The results of this study indicate clear diurnal variations in weightlifting performance, with significant differences in success rates, RPE, and weight lifted across different times of the day. The highest performance was observed in the evening (6 PM), while the lowest was in the early morning (6 AM) and late night (12 AM). These findings have important implications for the scheduling of training and competition sessions for weightlifters, suggesting that evening sessions might be most beneficial for achieving optimal performance.

Discussion

Interpretation of Results

The results of this study clearly indicate that weightlifting performance varies significantly across different times of the day, with the highest success rates observed in the evening (6 PM) and the lowest in the early morning (6 AM) and late night (12 AM). Specifically, the success rate at 6 PM was 73.1% (95% CI [71.0%, 75.2%]), which was significantly higher than the 68.2% (95% CI [66.1%, 70.3%]) success rate at 6 AM and the 68.5% (95% CI [66.4%, 70.6%]) success rate at 12 AM. These findings are supported by the ANOVA results (F(3, 199) = 5.67, p = 0.001) and subsequent Tukey’s HSD test, which highlighted significant differences between specific time points, particularly between 6 AM and 6 PM, and 12 AM and 6 PM.

The Rating of Perceived Exertion (RPE) also varied across times of the day, being highest in the morning (mean RPE = 7.5, SD = 1.1) and lowest in the evening (mean RPE = 6.2, SD = 0.8). This suggests that participants felt less strain during evening sessions, correlating with higher success rates and greater weights lifted (mean weight lifted at 6 PM = 129.3 kg, SD = 13.9 kg).

Comparison with Previous Research

The findings of this study are consistent with existing literature on diurnal variations in athletic performance. Previous research has demonstrated that physical performance, including strength, power, and anaerobic capacity, tends to peak in the late afternoon and early evening. Chtourou and Souissi (2012) reviewed multiple studies and found that most physical performance variables are better in the afternoon and evening compared to the morning. Similarly, Sedliak et al. (2008) reported higher maximal isometric strength and rate of force development in the evening.

In weightlifting specifically, Souissi et al. (2007) and Zarrouk et al. (2016) found that performance in the snatch and clean and jerk lifts was significantly better in the evening. The success rates in these studies aligned closely with our findings, reinforcing the reliability of the observed diurnal patterns.

Potential Mechanisms

Several biological, psychological, and environmental factors may underlie the observed diurnal variations in weightlifting performance:

Biological Factors:

Circadian Rhythms: Core body temperature, which follows a circadian rhythm, peaks in the late afternoon and early evening, enhancing muscle flexibility, enzymatic activity, and overall performance (Reilly & Waterhouse, 2009). Our findings of higher success rates and weights lifted in the evening align with this pattern.
Hormonal Fluctuations: Testosterone levels, although higher in the morning, may not translate to peak performance due to other synergistic factors being more favorable in the evening. Cortisol, a stress hormone, tends to be lower in the evening, reducing physiological stress and potentially improving performance (Hayes et al., 2010).

Psychological Factors:

Perceived Exertion: Lower RPE in the evening sessions suggests that participants felt less fatigued and more capable during these times. This aligns with findings by Drust et al. (2005), who noted that perceived exertion tends to be lower when core body temperature is higher.

Environmental Factors:

Routine and Habits: Many athletes may be more accustomed to training in the afternoon and evening, as these times are typically more convenient. This habitual training time could contribute to better performance due to established routines and psychological readiness (Hill et al., 1989).

Practical Implications for Athletes and Coaches

The results of this study have important practical implications for athletes and coaches:

Training Schedules: Training sessions might be optimized by scheduling them in the late afternoon or early evening to align with the body’s natural performance peaks.
Competition Planning: Where possible, athletes should aim to compete during their optimal times of day. For weightlifters, this means prioritizing late afternoon and evening competitions.
Recovery Strategies: Understanding the impact of circadian rhythms can help in planning recovery strategies. Training too early in the morning or too late at night might increase perceived exertion and fatigue, potentially leading to overtraining or injury.

Limitations of the Study

Despite its strengths, this study has several limitations:

Sample Size: While 200 participants provide a substantial data set, a larger sample might yield more generalizable results.
Generalizability: The study focused on competitive weightlifters aged 18-35, limiting its applicability to other age groups, recreational lifters, or athletes in different sports.
Potential Confounding Factors: Factors such as individual chronotypes (morningness or eveningness preference), nutrition, and sleep patterns were not controlled for, which could influence performance. Future studies should consider these variables to provide a more comprehensive analysis.

In conclusion, this study confirms significant diurnal variations in weightlifting performance, with peak performance observed in the late afternoon and early evening. These findings have practical implications for optimizing training and competition schedules and contribute to a deeper understanding of the interplay between circadian rhythms and athletic performance.

Conclusion

Summary of Key Findings

This study aimed to investigate how the percentage of successful and unsuccessful attempts in weightlifting is distributed across different times of the day. The research involved 200 competitive weightlifters who participated in lifting sessions at four specific times: 6 AM, 12 PM, 6 PM, and 12 AM. Our findings revealed significant diurnal variations in weightlifting performance, with the highest success rates observed in the evening (6 PM) and the lowest in the early morning (6 AM) and late night (12 AM).

The overall success rate across all sessions was 71.5% (95% CI [70.2%, 72.8%]), with a failure rate of 28.5% (95% CI [27.2%, 29.8%]). At 6 PM, the success rate peaked at 73.1% (95% CI [71.0%, 75.2%]), while it was lowest at 6 AM with a success rate of 68.2% (95% CI [66.1%, 70.3%]). The ANOVA results (F(3, 199) = 5.67, p = 0.001) and subsequent Tukey’s HSD test confirmed the statistical significance of these differences, particularly between 6 AM and 6 PM, and 12 AM and 6 PM.

Additional findings indicated that the Rating of Perceived Exertion (RPE) was highest in the morning (mean RPE = 7.5, SD = 1.1) and lowest in the evening (mean RPE = 6.2, SD = 0.8). The mean weight lifted also followed a similar pattern, with the highest mean weight lifted at 6 PM (129.3 kg, SD = 13.9 kg) and the lowest at 6 AM (120.5 kg, SD = 15.3 kg).

Implications for Future Research

While this study provides robust evidence of diurnal variations in weightlifting performance, several areas warrant further investigation:

Larger Sample Sizes: Future research should involve larger and more diverse samples to enhance the generalizability of the findings. Including athletes from various sports and levels of expertise could provide a broader understanding of time-of-day effects.
Longitudinal Studies: Longitudinal studies could examine how these diurnal patterns evolve over extended periods of training and competition, offering insights into long-term adaptations.
Individual Chronotypes: Research should explore the influence of individual chronotypes (morningness-eveningness preferences) on performance. Understanding how individual differences in circadian rhythms impact performance could lead to more personalized training regimens.
Interaction with Other Factors: Future studies should consider the interaction between time of day and other variables such as nutrition, sleep quality, and psychological state. Multivariate analyses could uncover complex relationships influencing athletic performance.
Female Athletes: Given the hormonal differences between genders, more research is needed on female weightlifters to determine if similar diurnal patterns exist and how menstrual cycles interact with these patterns.

Recommendations for Athletes and Coaches Regarding Training Times

Based on the findings of this study, several practical recommendations can be made for athletes and coaches:

Optimal Training Times: Athletes should schedule their training sessions in the late afternoon or early evening to align with the natural peak in physical performance. The highest success rates and the lowest perceived exertion were observed during these times, suggesting that training during this period could maximize performance and reduce fatigue.
Competition Scheduling: Where possible, athletes should aim to compete during their optimal times of day. For weightlifters, this means prioritizing competitions scheduled in the late afternoon or evening to exploit peak performance periods.
Personalized Training Programs: Coaches should consider individual chronotypes when designing training programs. Athletes who perform better in the morning might benefit from adjusting their schedules to match their personal peak times, while those who excel in the evening should capitalize on this period for intense training sessions.
Recovery and Rest: Understanding diurnal variations can also inform recovery strategies. Training too early in the morning or too late at night may increase perceived exertion and fatigue, potentially leading to overtraining or injury. Adequate rest and recovery should be emphasized, especially when training sessions are scheduled outside the athlete’s optimal performance window.
Monitoring and Adjustment: Continuous monitoring of performance metrics and perceived exertion can help in adjusting training schedules dynamically. Athletes and coaches should remain flexible and willing to adapt schedules based on performance data and recovery needs.

Final Remarks

This study underscores the significant impact of time of day on weightlifting performance, with clear evidence that performance peaks in the late afternoon and early evening. These findings contribute to a growing body of literature on circadian rhythms and athletic performance, providing valuable insights for optimizing training and competition schedules. By aligning training times with natural performance peaks, athletes can achieve better results, reduce the risk of injury, and enhance overall performance.

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Diurnal Variation in Weightlifting Success Rates: A Statistical Analysis