A new study investigating the immediate effects of breast implants on the body has found that they can produce subtle changes in muscle activity around the shoulder blades and slightly reduce a person’s reaching ability. These short-term changes, however, did not appear to cause significant negative shifts in overall posture or balance in healthy young women. The research was published in the journal Applied Sciences.
The decision to conduct this research was prompted by trends in cosmetic surgery. Breast augmentation is one of the most common surgical procedures performed worldwide. At the same time, the number of women choosing to have their implants removed has also grown. While complications like infection are known reasons for removal, researchers have become interested in less-discussed issues, such as the development of musculoskeletal and postural problems. An added weight on the front of the body could disrupt posture and lead to dysfunction over time.
Diana C. Guedes and a team of researchers from the Polytechnic of Porto in Portugal noted that much of the existing research focused on women with naturally large breasts or on patients who received implants for reconstruction after a mastectomy. A gap existed in understanding the immediate biomechanical effects of cosmetic implants on healthy women. The team aimed to explore how adding weight to the chest area, simulating common implant sizes, would instantly affect postural control during both static and dynamic tasks.
To investigate this, the scientists designed a cross-sectional study involving 35 healthy female volunteers with an average age of 24. Participants were excluded if they had a history of breast surgery, were pregnant, or had any existing conditions that could interfere with their posture or movement.
The study was designed to simulate breast augmentation, isolating the effect of weight from the complexities of actual surgery. Participants were fitted with demonstration implants in three common volumes: 220, 315, and 365 milliliters. These sizes equate to a range of enhancements, from adding about one pound to the chest for a single-cup-size increase, to adding nearly two pounds for a larger, two-cup-size augmentation. The implants were held in place by a supportive sports bra, allowing the researchers to directly assess how the added frontal load immediately affected each participant’s posture and muscle activity.
Each participant was evaluated in a laboratory setting under four conditions in a randomized order: a control condition with no implants, and one condition for each of the three implant sizes. The researchers used a suite of advanced equipment to capture detailed information. A motion capture system with reflective markers placed on the spine tracked the angles of the head, neck, and back.
A force plate embedded in the floor measured the participant’s center of pressure, which indicates small shifts in balance and stability. To measure muscle function, the team placed eight surface electromyography sensors on the dominant side of each participant’s body. These sensors recorded the electrical activity of key muscles in the neck, upper back, chest, and abdomen.
The participants performed two main tasks. The first was a static test where they were asked to stand still on the force plate for one minute. The second was a dynamic assessment called the Functional Reach Test. For this test, participants stood and reached forward with their dominant arm as far as they could without losing their balance or moving their feet. This test measures stability during movement. Alongside these physical measurements, participants also filled out questionnaires to describe their subjective feelings of comfort, effort, and the perceived weight of the implants for each condition.
When analyzing the data from the one-minute standing test, the researchers found that the added weight of the implants did not cause any significant changes to the participants’ spinal alignment. Their head, neck, and back posture remained consistent across all four conditions. Similarly, the force plate measurements showed no meaningful differences in their balance. The participants were able to stand just as steadily with the implants as they could without them.
The muscle activity data from the standing test revealed a more complex picture. For most of the muscles monitored, there were no significant changes in activity. One muscle, the levator scapulae, which helps lift the shoulder blade, showed an unexpected pattern. Its activity was significantly lower when participants wore the smallest 220 milliliter implant compared to the control condition with no implant. This suggests that the body’s response to a new frontal load is not a simple case of muscles working harder, but may involve more intricate adjustments in neuromuscular control.
During the Functional Reach Test, the research team observed a clear difference in performance. When wearing any of the three implant sizes, participants were not able to reach as far forward as they could in the control condition. Although the reduction in reach distance was small, it was statistically significant, indicating that the added weight had a subtle but immediate impact on their functional stability and mobility.
The muscle activity during the reaching test also showed notable adjustments, particularly in the large trapezius muscles of the upper back. When reaching forward with the 315 milliliter and 365 milliliter implants, participants showed increased activity in the lower part of the trapezius muscle compared to the control condition.
At the same time, activity in the upper part of the trapezius muscle decreased with some implant sizes. This suggests a shift in muscle strategy, where the body recruits the lower trapezius more heavily to help stabilize the shoulder blades against the forward pull of the added weight.
The participants’ subjective reports aligned with the physical changes. As the implant volume increased, their perception of comfort decreased. They also reported that the tasks required more effort and that the implants felt progressively heavier. Even with the largest size, however, participants generally described the experience as comfortable and requiring only light effort, showing good short-term tolerance for the added weight.
The findings suggest that in this group of young, healthy, and physically active women, the body is capable of making immediate, subtle adjustments to manage the added load of common implant sizes without a major disruption to overall posture.
The authors pointed out some limitations to their study. The research captured only the immediate, short-term effects of the simulated implants, and the long-term consequences of carrying such weight could be different. The study’s sample consisted of a homogenous group of young, active women with a normal body mass index, which may not be representative of all individuals who seek breast augmentation. Using a sports bra to hold the implants is also not identical to having them surgically placed within the body, which involves tissue healing and other physiological changes.
Future research could build on these findings by conducting long-term studies that follow women after they have had augmentation surgery. Including a more diverse sample with different ages, body types, and physical activity levels would also provide a more complete understanding of how implants affect the body.
The results of this study offer a baseline understanding, suggesting that while common implant sizes may not cause immediate biomechanical harm in healthy individuals, they do prompt the neuromuscular system to adapt. This information could be useful for surgeons and physical therapists in advising patients on implant size and postoperative care.
The study, “The Influence of Artificial Breast Volume Induction on Postural Stability, Postural Orientation, and Neuromuscular Control in Healthy Women: A Cross-Sectional Study,” was authored by Diana C. Guedes, Daniela F. Carneiro, Leonel A. T. Alves, Ana S. C. Melo, Juliana Moreira, Bruno Cunha, Rubim Santos, Andreia Noites, and Andreia S. P. Sousa.
