Any activity which increases the body temperature by few degrees Celsius is called as warm up [1]. In attaining optimum performance warm up prior to exercise plays a vital role [2]. The effects of warm up are seen in the overall sports performance and reduction in sports injuries due to internal factors [3].
Passive warm up helps in improving athletic performance by increasing flexibility [7], increase in oxygen release in the tissues [8], increase in metabolism of energy systems [9], increase in nerve conduction velocity [10], reduction in peak tension time in muscles [11], it can increase the temperature strain on the body and can help in increasing performance [12]. Active warm up helps increase in blood flow [13], increase in baseline Oxygen consumption [14], it leads to breaking of actin and myosin bonds which improves flexibility [11]. There is increase in post-activation potential [15]. There is increased preparedness for a sports activity after active warm up [16].
Short term muscle performance and dynamic stability are two parameters of athletic performance [17]. Increase in the muscle performance reduces injury and improves athletic performance [18]. There can be enhancement in motor skills from balance training resulting in increase in the rate of force development and thus, improving athletic performance [19].
However, there is a lack of literature on comparison of active and passive warm up on muscle performance, dynamic stability and effects of passive warm up on dynamic stability are not present. Therefore, aim of our study was to find out the effects of passive, active and combined warm up on lower limb muscle performance and dynamic stability in recreational sports players. If the muscle performance and dynamic stability of athletes is superior to any of the types of warm up, then it can be included in the athletic programs for improving performance.
Materials and Methods
The study was a randomized crossover trial carried out from October 2015 to March 2016. Institutional ethical clearance was obtained for the study. Twenty seven recreational sports players of both genders aged between 18-30 years playing lower limb dominant sports like basketball, volleyball, athletics and football were included in the study. Sample size was calculated using the formula
n= (Z1-α/2 + Z1-β) 2σ2 / d2,
where n= sample size, Z1-α/2= 2.395 at 5% level of significance, Z1-β =1.64 at 90% power, σ+ anticipated standard deviation -4.28, d= minimum significant difference -4 cm.
Sample size was calculated based on VJT as primary outcome measure. Subjects having a recent history of the upper quarter, lower quarter injuries and impaired sensations were excluded from the study. All subjects were screened for inclusion, exclusion criteria and were selected in the study. Allocation of the subjects has been explained in [Table/Fig-1]. Participation information sheet was given to the subjects and informed consent was obtained. Subjects who were included in the study went through three different warm up sessions, namely passive, active and combined warm up explained in [Table/Fig-2] and were required not to be involved in vigorous physical activity as it could hinder their performance in the study. Passive warm up was given using moist heat heating device that included eight Chattanooga original hydrocollator moist heat hot packs, standard-size (10″ W x 12″ L). Leg press exercise and stationary bicycle were used for active warm up. BOSU® ball exercises were used to give balance training. Sargent VJT and SEBT were used to access muscle performance and dynamic stability respectively.
Identification to completion of study participants (LBP-Low back pain, ACL-Anterior Cruciate Ligament).
Allocation and procedure for six groups.
Sargent VJT: VJT was the primary outcome measure that was used for assessing the muscle performance in the study. The participant stood facing a smooth dark wall with feet on the ground and toes touching the wall. The participant then reached as high as possible and marked the point with the chalk powder on the wall (taken as P1). The athlete then jumped as high as possible and marked another point at the peak of the jump (taken as P2). This was repeated thrice. The difference between P1 and P2 was measured and the best of three was considered [20].
Star Excursion Balance Test: SEBT was used as a secondary outcome measure used for assessing dynamic balance. The standard SEBT procedure was used where the participant stood on the ground. The participant was asked to use the non-stance limb to reach maximally to touch a point along one to eight designated lines on the ground. The test was performed first with non-dominant leg and the dominant leg. Best of three readings were recorded [21].
Passive Warm Up: Passive warm up group received moist heat as intervention. Moist heat packs were applied over hamstrings, quadriceps, gastro-soleus complex and over the gluteus muscles at the same time for a period of 20 minutes. The subjects rested in the prone position during the application. Subjects were asked not to sleep and were asked from time to time about the intensity of heat. Following passive warm up, self-stretching of the lower limb muscles was done by the subject. Hamstrings, quadriceps, gastro-soleus and gluteus muscles were stretched.
Active Warm Up: Active warm up session included exercises as the intervention. It started with five minutes of cycling on static cycle at 40 rpm followed by five leg presses with half the body weight, five squat jumps, five jump squats, five heel raises and one minute BOSU® ball balancing exercise with eyes closed and externally given perturbations. Stretching followed after active warm up exercises as explained earlier.
Combined Warm Up: Combined warm up included both passive warm up and active warm up exercises. Only difference in active warm up exercises and combined warm up was that the total duration of cycling and BOSU® ball exercise was reduced to half and other activities were reduced to three repetitions instead of five. Self-stretching of lower limb muscle followed combined warm up.
Statistical Analysis
Data was analysed using Statistical Package for Social Sciences (SPSS) version 15.0. Descriptive statistics were used for demographic variables. Data followed a normal distribution since standard deviation was less than twice the mean. Both the outcomes were assessed using repeated measures ANOVA.
Results
The descriptive statistics for the demographic characteristics demonstrated in [Table/Fig-3]. Test outcomes were assessed using repeated measures ANOVA. Mean and standard deviation for VJT for passive, active and combined warm up is 47.62±9.64, 48.50±10.16 and 48.87±10.70 respectively, demonstrated in [Table/Fig-4]. There was no significant difference present between warm up trials as the mean difference between passive-active, active-combined and combined-passive is -0.88, -0.37 and 1.25 respectively demonstrated in [Table/Fig-5].
Demographic characteristics of participants.
| Parameters | Minimum | Maximum | Mean±SD |
|---|
| Age (years) | 18.00 | 24.00 | 21.12±1.97 |
| Height (cm) | 153.50 | 188.50 | 171.79±8.63 |
| Weight (Kg) | 48.00 | 82.00 | 65.58±11.16 |
Mean and SD for warm up trials in VJT and SEBT.
| Warm ups | Mean±SD (VJT) | Mean±SD (SEBT) |
|---|
| Passive | 47.62±9.64 | 85.43±8.61 |
| Active | 48.50±10.16 | 85.17±8.60 |
| Combined | 48.87±10.70 | 85.17±8.38 |
Mean difference and p-value between warm up trials in VJT and SEBT.
| Warm ups | VJT: mean difference, p-value* | SEBT: meandifference, p-value* |
|---|
| Passive-Active | -0.88 (0.67) | 0.262 (1.00) |
| Active-Combined | -0.37 (1.00) | -0.002 (1.00) |
| Combined-Passive | 1.25 (0.51) | -0.260 (1.00) |
*Using repeated measure ANOVA
The mean and standard deviation for passive, active and combined warm up [Table/Fig-4] are 85.43±8.61, 85.17±8.60 and 85.17±8.38. There is no significant difference between warm up trials as mean difference [Table/Fig-4] is 0.262, -0.002 and -0.260 for passive-active, active-combined and combined-passive warm up respectively and also.
Discussion
Our study shows that the type of warm up does not influence muscle performance and dynamic stability. There is no significant difference in either of the warm up trials that was assessed using VJT and SEBT [20,21].
Passive warm up when compared with active warm up shows no significant change with respect to muscle performance and dynamic stability. These results are similar to the study results of Demura T et al., [22]. They had used gentle gripping exercises over a sponge as an active warm up and passive heating of flexors of forearm using polarized radiation [22].
These similar results can be because of the temperature related effects of passive warm up while temperature and non temperature related effects in active warm up [23]. There can be formation of metabolities like lactate in muscles as well as reduction in enegry substrates which can be one of the reaseon for equal performance [24]. Active warm up has positive effect of increasing flexibility by breakdown of actin and myosin [25]. Whereas, there could have been preservation of energy substrates and the positive temperature related effects in case of passive warm up that might have led to similar performance with respect to active warm up [26].
Our study results are different from the study results found by Yaicharoen P et al., who found passive warm up better over active warm up with respect to power and work done during intermittent sports performance [23]. This can be because of the difference in the method of passive warm up and the outcome measure used. They had used hot water immersion for 45 minutes as a passive warm up because of which there would have been more heating of the body that led to better performance and they had used intermittent sprint as outcome measure which uses anaerobic system as a source of energy [23]. ATP-PCr and muscle glycogen may be preserved during passive warm up [27]. As these are anaerobic system substrates, it may have resulted in muscle performance difference resulting in passive group muscle performance to be superior.
A study was done to compare the effects of different types of warm ups on swimming performance, they found there was no influence of type of warm up on the performance of swimmers. However, in this study passive warm seemed to be appropriate, but they recorded a lower self-confidence [28].
In this study, there was no significant differences found in SEBT measures between the two warm up techniques. This can be because of reduction of muscle and fascia viscosity due to thermal effect of passive warm up [29]. This might have led to improved flexibility in the muscles and fascia and thus, similar reach distance on SEBT in passive warm up group compared to active warm up group [30].
Combined warm up didn’t show any significant change with respect to VJT and SEBT compared with active and passive warm up. One reason can be that the effects of passive warm up are nullified by active warm up. The preservation of energy substrates during passive warm up may have got utilized to more extent during active warm up session [2].
Though the time and activities in active warm up which is a part of combined warm up was less as compared to active warm up alone, passive warm up prior to active warm up could have led to faster utilization of energy substrates [31]. This may have resulted in reduction in energy substrates that led to non-significant differences in between the warm up trials in VJT and SEBT.
Though combined warm up was not statistically significant different from passive and active warm up, we found VJT outcome measures better in combined warm up trial than after passive and active warm up trial. Even this small increment in performance might benefit the players during sports events.
Passive warm, active and combined warm up can be used in short term high intensity muscle activities like high jumps, long jumps, sprinting, gymnastics, but the selection of warm up will be based on athletes and the requirement of a particular sports event. Like in case of short duration, high intensity activities which require mainly anaerobic energy substrates, passive warm up would be better as there is preservation of energy substrates that can be utilized during sports activity. No activity during passive warm up results in non-formation and collection of metabolites in the blood which can also improve sports activity.
Limitation
This study had a few limitations like the extent of rise in muscle temperature between the warm up trials was not considered. Thus, we can’t say that the thermal effects were equal in all the three groups. Also, the effects of warm up trials were not tested on high intensity short duration muscle performances. So the extent of utilization of the anaerobic energy substrates was less during VJT and SEBT would have been less. So this can be the reason for not getting any difference in muscle performance. May be a larger sample size would have also shown change in performance of each group.
Still further research is needed in the same area using other passive methods like hot water immersions. Also, other tests to check vigorous sports performances like high intensity sprinting can be used. The extent of rise in the core and muscle temperature can also be monitored. The effects of passive, active and combined can also be tested on intermediate sports performances and similar studies can be done on professional sports players.
Conclusion
All three types of warm ups had similar effects on muscle performance and dynamic stability in recreational athletes. Any of these warm up techniques can be used by a recreational athlete to improve their performance in the sports. However, more research is needed in this field to understand the efficacy of these warm up trials in different sports scenarios.
*Using repeated measure ANOVA