Yoga is a popular sport among many urbanites in recent years. Apart from relieving stress, it can also help strengthen muscles and improve flexibility. A pair of comfortable and stretchy yoga pants can enhance the comfort and workout performance. In recent years, many people wear yoga pants as casual wear, with an abundant supply of styles at a wide range of prices. The Consumer Council tested 20 models of women's yoga pants on the market and found considerable variance in the performance of stretch and recovery, with elongation varying by about 1.3 times in length and 3.5 times in width respectively. Some models had a noticeable reduction in their stretchability after a number of washes, and the highest reduction found was 108% in width elongation. In addition, 1 model was found with a slow moisture evaporation rate, while 2 models might stain other clothing after being soaked with perspiration. The overall performance of most models was satisfactory. Models with an overall rating of 4.5 or above ranged from $149 to $880 in price, reflecting that there is no necessary correlation between product quality and price. Therefore, apart from style and brand preferences, consumers should choose wisely based on their budget and the intended use of the product such as for casual wear, or for specific types and intensity of exercise.
The Council tested 20 models of women’s yoga pants. All models were leggings, 7/8 length or full-length and high-waisted, with prices ranging from $149 to $980. 12 of them claimed to be suitable for yoga exercises, while the remaining 8 only claimed to be sports pants or leggings. The test items covered stretch and recovery performance, comfort, durability, accuracy of fibre composition labelling, and chemical safety of the models.
Vast Variation in Stretch Performance
Yoga exercise typically involves a wide range of stretching poses, which require yoga pants to have good elasticity for comfort and freedom of movement. Elasticity covers both stretch and recovery. The test simulated fabric stretching during daily wear, and the tested samples were pulled back and forth 5 times with a force of 20N to evaluate their stretch and recovery performance in both lengthwise and widthwise directions. The test results revealed substantial variation in elongation, ranging from 78.1% to 177% in lengthwise elongation, a difference of about 1.3 times and a range of 61.8% to 277.1% in widthwise elongation, an even greater difference of around 3.5 times. Overall, most models had a high level of stretchability, among which 9 models performed satisfactorily with width elongations of over 200%.
To maintain hygiene, sportswear should be washed after wear, but most models showed reduced elongation after 50 washes, the main reason being that the structure and density of fabric would change after washing, resulting in either increased or decreased elongation. The largest difference was found in 1 model, whose widthwise elongation was reduced by approximately 108%. However, 1 model showed improvement in stretch performance after washing, with an increase of around 9% and 35%, in length and width elongation respectively.
Yoga pants with good stretch performance also need good recovery to prevent becoming deformed after stretching, which may affect the durability and appearance of the pants. Most models had satisfactory recovery performance, with a recovery rate of over 90% for length and/or width with the measurement taken 30 minutes after stretching. After 50 washes, most models only showed a slight reduction in recovery of less than 10%. The pants were still able to maintain their shape without disfiguration.
Up to 4-fold Difference in Moisture Evaporation Rate
Satisfactory Performance in Breathability
The comfort of sportswear is largely dependent on the fabric’s quick-drying performance and breathability. The quick-drying performance of the pant models was evaluated by draping the tested sample (15cm x 15cm) over an electric hot plate that simulated human skin. Subsequently, 0.2ml of water was added to the hot plate. The moisture evaporation rate was calculated by measuring the temperature change in the tested sample. The results showed that the slowest-drying model could only evaporate 0.38ml of water per hour (approximately 2 droplets of water), a 4-fold difference in comparison to the fastest-drying model (2.03ml/hour). Models with a slower moisture evaporation rate tend to retain sweat for a longer period of time, and the wearer may feel damp and sticky while sweating and some individuals may even experience itchy skin, rashes, or allergies due to accumulation of sweat.
Yoga pants with high degrees of breathability can quickly repel the water vapour from the skin and also body heat to keep the skin dry. The breathability of the yoga pants models was assessed by measuring the amount of water vapour that permeated through to the outer layer over a 24-hour period. All models were found to have rather high degrees of breathability, of which 5 models were measured with a water vapour permeability of 1000g/24hr/m2 or more, which would keep the wearer dry and comfortable.
Colour Faded or Bled after Washing or Sweating
1 with Inaccurate Fibre Composition Labelling
Poor colourfastness in yoga pants can lead to fading after washing or being eroded by perspiration. In worst cases, they may even transfer colour and stain other clothing. Most models showed discolouration to various extents after 50 washes, out of which 2 models were found with serious discolouration on the pants body or pockets, while the print on 1 model detached after washing. Furthermore, 4 models showed slight pilling after repeated washing, which not only affected their appearance, but also posed a risk of the fibre tangling and potential damage during the wash process.
The colour on the body or pockets of 2 pant models stained other fibres in the test after being soaked with simulated sweat, indicating a possibility of colour bleed to other garments, among which 1 model also showed similar colour bleed after washing.
In terms of chemical safety, all models complied with the requirements of relevant standards, but 2 models were detected with a small amount of free formaldehyde.
As for the labelling of fibre composition, 1 model showed an 8.2% discrepancy between the labelled and actual composition. According to EU regulations, the discrepancy between the labelled and the actual composition of blended fibres should not be more than 3%. The Council urges the manufacturer to improve the accuracy of the fibre label. The test results have also been referred to the Customs and Excise Department for follow-up.
Consumers can refer to the following tips for the purchase and care of yoga pants:
- Choose the yoga pants or leggings based on the type and intensity of exercise. Before buying, try them on, and if there are any marks found on the skin after taking the pants off, it indicates that the size is too small, which may hinder blood circulation and affect comfort;
- Wash them as soon as possible after wearing them. Keeping sweaty clothes for an extended period increases the likelihood of bacteria and mould growth, resulting in unpleasant odour, whereas the pH value of sweat would also impact the fabric’s elasticity. Do not use fabric softeners when washing, as it would trap dirt in fibres, leave the smell on the pants and spoil the elasticity of the materials;
- Do not wash or tumble dry yoga pants at high temperatures and do not iron, so as not to damage the wicking and elastic performance, and to avoid shrinkage, deformation or discolouration;
- To machine wash yoga pants, it is advisable to turn them inside out, put them in a laundry bag and wash at a low speed to avoid scratches from sharp objects.
Download the article (Chinese only): https://ccchoice.org/562yogapants
Consumer Council reserves all its right (including copyright) in respect of CHOICE magazine and Online CHOICE.