{'fraction_non_alphanumeric': 0.03025347506132461, 'fraction_numerical': 0.020032706459525755, 'mean_word_length': 4.677494199535963, 'pattern_counts': {'":': 0, '<': 3, '<?xml version=': 0, '>': 2, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Acute Effects of Cold Pack for Different Periods on the Biomechanical Properties of the Rectus Femoris Muscle.

Context
Cold packs are silica gel packs that are commonly used in clinics. However, the packs are applied for various amounts of time, and the relationship between these times and temperature changes isn't fully understood.


Objectives
The study intended to investigate the acute effects of cold-pack application for different periods of time on the biomechanical properties of the rectus femoris muscle.


Design
The study was randomized, controlled trial.


Setting
The study took place at Acibadem Mehmet Ali Aydinlar University in Istanbul, Turkey.


Participants
Participants were 60 healthy volunteers from the community, aged 18 to 23 years.


Interventions
Participants were divided into four groups with n = 15 in each group. The cold packs were applied on the dominant rectus femoris muscle: (1) for 10 minutes in Group 1, (2) for 12 minutes in Group 2, (3) for 15 minutes in Group 3, and (4) for 20 minutes in Group 4.


Outcome Measures
The outcome measures were the skin temperature, determined using a thermal camera, and biomechanical properties-tone and stiffness and muscle decrement-using a device that delivers a short mechanical impulse to the tissue. Outcomes were measured at baseline before the cold application, immediately post intervention after the cold application, and at 5, 10, 15, 20, and 30 minutes post intervention.


Results
The mean skin temperatures were significantly lower in all groups compared to those before cold application (P < .05), and no significant differences existed between any of the groups (P > .05). Post intervention, while Groups 1 and 2 showed an increase in muscle tone and stiffness and a decrease in elasticity (P < .05), they began to approach their baseline state by the fifth and fifteenth minutes, respectively (P > .05). In Groups 3 and 4, the muscle stiffness increased at all time points (P < .05).


Conclusions
The study showed that the rectus femoris muscle of healthy people becomes stiffer and less elastic as a result of cooling with cold packs that were applied for different time periods. The amount of cold-pack time that minimized the biomechanical corruption of the muscle and provides cooling was 10 minutes. Careful warming up is recommended before and after intense athletic performance, and caution in cooling the skeletal muscle should be exercised.