Static versus dynamic stretching; short term effects on physical performance in non-athletes- a randomized clinical trial

Abstract

Background: Non-athletes have varying fitness levels, muscle characteristics, and training backgrounds, which can affect how different types of stretching exercises impact their physical performance. 

Objective: to compare the acute effects of static and dynamic stretching on physical performance of non-athletes. A single-blinded, cross-over, randomized clinical trial was conducted at Iqra National University, Peshawar for a period of 6 months. A total of n=54 male participants were randomly allocated into group A and B. Group A performed the static stretching while group B performed dynamic stretching. The physical performance measure was endurance, agility, strength, flexibility, and balance respectively. 

Result: The result of two-way RMANOVA showed that both stretches had significant interaction effects between interventions and all performance measures (p<0.001) except for balance (p=0.23). The main effect showed that static stretching significantly reduced agility and balance (p<0.05), while dynamic balance improved all measures significantly (p<0.05). When comparing the mean differences of all variables, dynamic stretches showed significant improvement (p<0.05) in all variables as compared to static stretching. 

Conclusion: Dynamic stretch has a significant contribution to improving all physical performance measures among non-athletes if incorporated before the activity. While static stretching negatively affects the agility and balance among this population. (NCT05053490) 

Keywords: agility; balance; dynamic stretching; endurance; flexibility; non-athletes; physical performance; static stretching.

INTRODUCTION

Non-athletes are individuals who do not engage in regular or organized athletic activities or sports. They may still engage in physical activity for health and fitness purposes, but their level of participation in sports or athletic events is limited or non-existent [1]. Physical fitness among non-athletes can vary widely depending on individual lifestyle choices and level of physical activity. While non-athletes may not participate in organized sports or athletic events, they can still engage in regular physical activity for health and fitness benefits[2].

Growing evidence suggests that physical performance and lifestyle behaviors in the early years of life contribute to chronic diseases in the older population [3]. Stretching exercises can improve flexibility, posture, blood circulation and reduce stress [2, 4]. Which ultimately improves joint mobility, reduces muscle soreness and pain as well as have a positive impact on improving physical performance by allowing for greater ease of movement. Mental health and quality of life [5, 6]. Static stretching and dynamic stretching are two types of stretching exercises that commonly involve lengthening muscles and improving flexibility thus the physical performance [7]. They differ in terms of their timing and the movements involved. Static stretching involves holding a stretch for an extended period, usually 15-30 seconds, without any movement [8, 9]. 

Static stretching is typically performed after a workout when the muscles are warm and is often used to improve overall flexibility [10, 11]. Dynamic stretching, on the other hand, involves moving through a range of motion that mimics the activity participating in[12]. Dynamic stretching is usually done before a workout or activity to warm up the muscles and prepare the body for the specific movements required in the activity[10]. Research has shown that both static and dynamic stretching can have immediate effects on physical performance, but the effects may differ depending on the type of stretching and the timing of the performance test[13]. Dynamic stretching can improve power and strength immediately after stretching, while static stretching may lead to a decrease in power and strength immediately after stretching. However, the exact timing of these effects may vary depending on the individual, the activity being performed, and the type and duration of stretching used [12, 14, 15]. 

Although there is a lot of literature available on the athlete population regarding both types of stretching, the non-athlete population is still under study. The non-athletes may experience static and dynamic stretching exercises differently depending on their individual preferences, muscular stiffness, muscle activation, injury prevention, performance enhancement, and other considerations. For non-athletes interested in a variety of sports and physical activities to enhance their health, endurance, increasing strength, flexibility, and physical performance is crucial. Understanding the immediate and short-term impacts of these stretching strategies on physical performance is the goal of evaluating the effects of static and dynamic stretching during a single session on physical performance at various time periods. To maximize the physical performance of non-athletes, the impacts at various time periods can be compared to discovering the best timing for executing these stretches. Thus, the objective of the current study was to compare the acute effects of static and dynamic stretching on non-athletes' physical performance at various time points.

MATERIALS AND METHODS

A single-blinded, crossover, randomized clinical trial was initiated after getting approval from the Research Ethical Committee (REC) of Riphah International University, Islamabad. The study was conducted at Iqra National University, Peshawar from June 2021 to December 2021. The purpose of the study was explained to the subjects and written informed consent in accordance with Deceleration of Helsinki was obtained from the study participants. 

Non-probability convenient sampling technique was used for sample collection. The non-athlete males, aged between 18-25 years, decreased Range of Motion (ROM) of the lower limb including hip flexion (SLR)>80 degrees, knee flexion>130 degrees, and ankle dorsiflexion>20 degrees, and had normal body mass index (BMI) were included in the study. However, participants who had acute injuries of lower limbs, active sports any training programs, and had lower limb disabilities were excluded from the study. 

A total of n=56 sample size was calculated through G power, keeping the effect size small (0.2), with α error margin at 0.05. To avoid β error probability, the power (1- β) was set at 0.95%. A total of n=298 male non/recreational athletes were evaluated for the inclusion criteria, n=242 participants did not fulfill the selection criteria, so excluded from the study. A total of n=56 participants was then randomly divided into group A (n=28) and group B (n=28). One participant from each group did not complete the follow-up after the washout period, so in the final analysis, n=54 participants were included. (Figure 1) 

Figure 1. CONSORT Diagram.

The sealed enveloped method using a computerized random number generator was used for randomization. An individual who was not directly involved in the study did the random allocation. The random numbers were then written on the index cards and placed in a thick and opaque sealed envelope before the start of the study. After obtaining written informed consent, the physical therapist opened the envelope and provided the respective interventions to the patients. As the assessing physical therapist was blinded to the intervention so the study was single-blinded.

The intervention detail was explained to the subjects and none of the participants were harmed during the study. Each participant was assessed initially at the baseline and then stretching exercises were performed. Initially, group A received 7-static stretching, and group B received 8-dynamic stretching exercises. The assessment was done after 5 minutes, then 6 hours, and after 24 hours to measure short-term effects. After that, an interval of 3 days was given as a washout period. After the washout period interventions were switched, so group A received dynamic stretching protocol while group B received static stretching, and a similar assessment procedure was repeated to determine the difference. The force of the bounce or swing of dynamic stretching was taught to gradually increase while avoiding radical or uncontrolled movements.  Each dynamic stretch held at the end-range was for 2-3 seconds and then asked to take the joint through its range of motion. (Table 1)

These all exercises were performed by the participants actively under supervision after being demonstrated by the therapist, inside the physiotherapy laboratory of Iqra National University, Peshawar Pakistan. 

Table 1. Intervention protocol

The demographic data along with height, weight, BMI, and ROM of hip flexion, knee extension, and ankle dorsiflexion were obtained. The outcome measures were endurance, agility, strength, flexibility, and balance. The endurance was measured by Cooper's 12-minute walk/run test, a modified Illinois agility test was used to determine agility of the spine and pelvis, a vertical jump test determined the strength, flexibility was assessed through sit-and-reach test while functional reach test was used to determine balance. 

For within-group comparison, The Two-way repeated-measures ANOVA was used to see the interaction effects between intervention and assessments. For main effects, RMANOVA for with-in group changes and independent T-test to compare the mean differences (MD) of physical performance measures were used as the baseline differences existed. The level of significance was set at p<0.05 and SPSS version 28 was used to analyze the data. 

RESULTS

The mean age of the participants was 19.33±0.80 years. The height (in feet) and weight (in kg) were calculated with a mean of 5.6±0.15 feet and 69.77±2.98 kg respectively. The ROM was measured for hip flexion, knee flexion, and ankle dorsiflexion. The mean ROM for hip flexion was found to be 74.42±3.97 degrees, knee flexion was 133.50±2.28 degrees, and ankle dorsiflexion ROM was 19.50±2.48 degrees. 

The result of two-way RMANOVA showed that both stretches had significant interaction effects between interventions and endurance {F=35.72(1.56, 82.79), p<0.001, ηp²=0.40}, agility {F=310.52(1.78,94.8), p<0.001, ηp²=0.85}, strength (F=30.61(1.39,74.12), p<0.001, ηp²=0.36) with larger effect size. While between interventions and flexibility {F=7.08(1.24, 65.84), p=0.006, ηp²=0.11} interaction effect is small. However, the interaction effects of both types of stretching on balance {F=1.45(1.0,53.26), p=0.23, ηp²=.027) were insignificant. (Figure 2)

Figure 2. Interaction effect between the intervention and physical performance

The main effects showed that endurance, which was measured with the Cooper 12-minute walk test was significantly improved from baseline to after 24 hours in static stretching {F=8.48(1.85,98.41), p=0.001, ηp²=0.13} and dynamic stretching {F=88.597(1.53,81.44), p<0.001, ηp²=0.62}. The pairwise comparison showed static stretching significantly improved endurance from baseline to after 5 minutes (p=0.019) but no significant improvement was observed after 6 hours and 24 hours (p≥0.05). However, dynamic stretch showed a significant improvement in endurance throughout the session (p<0.001). Agility was measured with the modified Illinois agility test and the main effects showed significant decline in the agility {F=130.29(1.87,99.53) p<0.001, ηp²=0.71} from the baseline to after 24 hours as well as at each level of assessment. While in dynamic stretching group significant improvement was observed {F=308.11(2.11,112.33), p<0.001, ηp²=0.85} throughout the intervention duration.  

Furthermore, it was observed that the effects of both types of stretches, i.e., static stretch {F=30.67(1.48,78.53) p<0.001, ηp²=0.367} and dynamic stretch {F=192.79(1.69,89.81), p<0.001, ηp²=0.78} significantly improved strength. The pairwise comparison showed a significant improvement from baseline to after 24 hours in both stretches (p=0.001). Flexibility was also improved in both groups, static stretch {F=81.42(1.33,70.95), p<0.001, ηp2=0.60} and dynamic stretch {F=119.74(1.26, 67.11), p<0.001, ηp²=0.69}. A pairwise comparison of both techniques showed significant improvement throughout the sessions (p<0.001). The balance was measured by the functional reach test, which showed no significant improvement in static stretching {F=1.08(1.002,53.09), p=0.30, ηp²=.020} but significant improvement was observed in dynamic stretching {F=145.14(1.28,68.03), p<0.001, ηp²=0.73} from baseline to throughout the session. The pairwise comparison showed non-significant (p≥0.05) improvement in the balance from baseline to after 5 minutes in the static stretching group. However, a nonsignificant decline was observed from 5 minutes to 6 hours. In the last, from 6 hours to 24 hours, there was a significant (p<0.001) decline in the balance in the static stretching group. However, dynamic stretching showed significant improvement (p<0.001) throughout from baseline to after 24 hours as well as at each level of assessment. (Table 2)

Table 2. Within-group Analysis of Physical Performance Measures.

Figure 3. Comparison of mean differences (MD) of physical performance measures. 

Between-group analysis showed a significant difference between both types of stretching techniques (p<0.05).  The mean of the mean difference showed that dynamic stretching causes a significant increase in all components of physical performance with a large effect size when compared to static stretching including agility (1.85±0.60 vs -1.23±0.66, p<0.001, Cohen’s d=1.06) , strength (-2.76±1.15 vs -1.05±1.20, p<0.001, Cohen’s d=2.09), flexibility (-2.90±1.76 vs -1.95±1.42, p=0.008, Cohen’s d=2.54), balance (-4.19±2.21 vs 2.99±1.98, p<0.001, Cohen’s d=3.24) and endurance (-94.41±67.35 vs -18.63±36.24, p<0.001, Cohen’s d=83.17). (Figure 3)

DISCUSSION

The current study aimed to compare static stretching and dynamic stretching on non-athletes physical performance at various time points. The results suggested that dynamic stretching significantly improves all performance measures at various time points as compared to static stretching. Moreover, balance was immediately improved after stretching exercise but afterward declined, while agility declined throughout the intervention from baseline to after 24 hours.

The results showed that dynamic stretching causes significant improvement in all components of physical performance when compared to static stretching. In dynamic stretching muscles are stretched actively in a variety of dynamic activities challenging ROM at a constant rate[8]. Through a combination of central and local mechanisms, including improved neural activation, increased blood flow, enhanced motor unit recruitment, increased muscle temperature, improved muscle activation, improved joint range of motion, and improved muscle compliance, dynamic stretching can enhance physical performance measures [16-19].

In the current study, endurance showed improvement in both types of stretching which is in coherence with the literature [20]. Iwata et al studied the effects of dynamic searching, where a 30-second stretch had sustained effects for 90 minutes[21].  The current study measured the short-term effects to be sustained with the application of dynamic stretch, the difference in endurance was significant when the baseline was compared to 5 minutes, 6 hours, and 24 hours. In the static stretching group, short-term effects at different time points were not significant but after 24 hours endurance was improved. It was reported that reduction in maximum voluntary contraction (MVC) after static stretching (SS) which remained reduced for an hour. A possible reason for the decrease was purported to be originated by neural fatigue, which leads to a decrease in the recruitment of motor units and a reduction in performance. The changes that occurred in the aponeurosis-tendon complex may affect the proprioceptive response thereby decreasing motor unit activation [22, 23].

According to the results of this study, static stretching showed a significant reduction in agility and agility, while dynamic stretching significantly improved both at each point of assessment. So, a significant difference was observed between both types of stretching. The previous study reported the positive effects of static stretching on agility and performance [24]. however, in a study static stretching significantly reduced the agility and balance but dynamic stretching improved both [25].  The literature shows that static stretching has been demonstrated to reduce neuromuscular activation, temporarily reduce muscle strength, and impede communication between the brain and the muscles so reducing the reaction time. These effects may have a negative impact on agility as well as balance by diminishing the force, speed, and force production capability of the muscles [18, 26, 27]. Hence dynamic stretching is more effective in improving agility, which enhances performance. So, for agility and balance measures, dynamic stretching is better to incorporate before these activities. [16-19,28] 

Furthermore, strength and flexibility measured with vertical jump test and sit and reach test respectively were improved in static and dynamic stretching exercises in both groups. However dynamic stretching has more significant improvement as compared to the static stretching group.  The results of this study are in coherence with the previous study in which static and dynamic stretch improves the vertical jump test and range of motion of the hip and knee in active male college students[29]. Another meta-analysis on static stretching exercises in both athletic and non-athletic (recreationally trained) participants showed that static stretching was found to have a negative impact on maximal strength and power performance. The authors advised against using static stretching during a warm-up routine in light of these findings[30].

A study conducted by Perrier et al. stated significant improvement in flexibility after static and dynamic stretch. However, there weren’t significant between-group differences observed for flexibility [31]. However in the current study results are contradictory to the study, which shows improvement in both measures in static stretching as well as dynamic stretching groups. A systemic review and meta-analysis stated that dynamic stretching improves vertical jump and flexibility throughout stretching sessions [32]. The results of the current study are coherent with this previous study. Dynamic stretching exercises improve muscle activation, motor unit recruitment, and coordination to build muscular strength. These stretches can also increase joint mobility gradually, decrease stiffness, and increase overall flexibility. Dynamic stretching exercises may be a useful technique to increase strength and flexibility while also lowering the risk of injury when incorporated into a warm-up regimen[33].

Although the current study was a single-center study, the external validity of the result may be affected by to same population. Moreover, the current study tried to establish a cause-and-effect relationship between two types of stretching and physical performance measures at various time points based on available literature. 

CONCLUSION

Dynamic stretch has a significant contribution to improving all physical performance measures among non-athletes if incorporated before the activity. While static stretching negatively affects the agility and balance among this population. The effects of static and dynamic stretching exercises can differ among athletes and non-athletes with respect to individual preferences, muscular stiffness, muscle activation, injury prevention, performance enhancement, and other considerations, so further research should be on these differences as well as focused on a possible mechanism of effectiveness among non-athletes. 

DECLARATIONS & STATEMENTS

Author’s Contribution

SHK: substantial contributions to the conception and design of the study. 

MBI and JA: acquisition of data for the study. 

ZM and RK: interpretation of data for the study. 

AS and AHB: analysis of the data for the study. 

KK and AO: drafted the work. 

SHK, MBI, JA, ZM, RK, AS, AHB, KK and AO: revised it critically for important intellectual content. 

SHK, MBI, JA, ZM, RK, AS, AHB, KK and AO: final approval of the version to be published and agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All authors contributed to the article and approved the submitted version.

Ethical Statement 

The study was conducted in accordance with the Declaration of Helsinki and approved by the joint Research and ethical committee of Riphah International University (RIPHAH/RCRS/REC/Letter-01012) and Department of Allied Health Sciences, Iqra National University Peshawar Pakistan (INU/AHS/973-21).

Consent Statement

Informed consent was obtained from all subjects involved in the study.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Acknowledgments

Thanks to the participants of this study for sharing their personal experiences with pain.

Conflicts of Interest

The authors declare no conflict of interest  

Funding

The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.

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