Acute Effect of Heavy Weightlifting on the Pelvic Floor Muscles in Strength-Trained Women: An Experimental Crossover Study

ABSTRACT

Introduction/Purpose

Heavy lifting may produce strain on the pelvic floor muscles (PFM) due to high increases in intra-abdominal pressure, but knowledge of the impact of weightlifting on the PFM is lacking. Therefore, this study aimed to investigate acute effects of heavy weightlifting on the PFM in strength-trained women and whether general strength in whole-body exercises correlated to PFM strength.

Methods

Forty-seven nulliparous women between 18 and 35 yr who regularly performed weightlifting and were able to lift their own body weight × 1.2 in back squat and 1.5 in deadlift were included in this experimental crossover study. They participated in baseline evaluations (questionnaire/measurements of background characteristics and pelvic floor disorders, one-repetition maximum (1RM) tests in back squat and deadlift) and one test day where they were randomized to start with 60 min of weightlifting (four sets of four repetitions at 75%–85% of 1RM in back squat and deadlift) or seated rest of 60 min. Vaginal pressure measurements of PFM resting pressure, strength, and endurance and surface electromyography measurements of PFM resting activity were performed before/after weightlifting and rest.

Results

No statistically significant differences were found when comparing the change in PFM resting pressure, strength, endurance, and resting activity after heavy weightlifting and rest. There were no statistically significant correlations between PFM strength and maximum (1RM) or relative strength (1RM/bodyweight) in either back squat or deadlift.

Conclusions

Our results imply that heavy weightlifting is well tolerated by the PFM in short term among young, nulliparous, and strength-trained women. Strength in whole-body exercises was not correlated to PFM strength.

Strength training with free weights is currently the second most popular fitness trend worldwide (1). Furthermore, there has been a substantial growth in women participating in strength-specific sports and activities that may generate large increases in intra-abdominal pressure (2), such as Olympic weightlifting (3), powerlifting (4,5), and functional fitness training (6,7). The pelvic floor is situated in the abdominopelvic cavity and consists of ligaments, fascia, and muscles. In addition to providing support to the pelvic organs (bladder, urethra, vagina, uterus, and rectum in women), it must counteract increases in intra-abdominal pressure during physical exertion (8). To date, two opposing hypotheses regarding the impacts of intra-abdominal pressure during exercise on the pelvic floor exist (9). The pelvic floor muscles (PFM) may be strengthened because of possible training adaptions of indirect loading. In contrast, if the PFMs are not able to resist increases in intra-abdominal pressure, the pelvic floor may be stretched, overloaded, and weakened. This may cause pelvic floor disorders (PFD) such as urinary and anal incontinence (UI, AI) and pelvic organ prolapse (POP) (9). Recent studies show that PFD is common in female strength athletes, especially stress urinary incontinence (SUI; “involuntary leakage of urine on physical effort”) with prevalence rates ranging from 32% to 46% (10–13).

Overall, knowledge of the impacts of heavy lifting on the PFM and mechanisms of PFD in strength athletes is limited. Clinical studies investigating PFM variables in sport women show contradicting results with no clear conclusion (9), and there is a lack of such investigations in women performing strength exercises (9). Some also suggests that participation in sports may cause overactive PFM muscles (14), but further evidence is needed to support this claim. Vaginal manometry and surface electromyography (sEMG) measurements of the PFM before and after one bout of exercise can provide information on the immediate levels of exhaustion (fatigue) and alterations in muscle tone after exercise (15). These short-term assessments can be useful for a better understanding on how load affects the PFM and thereby mechanisms of PFD.

Therefore, our aim was to assess the acute effects of heavy weightlifting on PFM resting pressure, strength, endurance, and resting activity in nulliparous strength-trained women. In addition, we aimed to investigate if general strength in whole-body exercises was correlated to PFM strength.

METHODS

Participants

Nulliparous women between 18 and 35 yr of age who regularly participated in strength training (with ≥2 yr’ experience and ≥3 training sessions per week) and were able to lift their own bodyweight × 1.2 in back squat and 1.5 in deadlift, were included in the study. The exclusion criteria were as follows: previous pelvic surgery to correct POP, UI, or AI; ongoing pregnancy; and inability to perform the exercise protocol or a correct PFM contraction. Participants were recruited through social media (Facebook, Instagram) and in collaborations with weightlifting/powerlifting clubs and federations between December 2021 and October 2022. Eligible participants were invited to participate in two different test sessions (one baseline evaluation and one test day) at the Norwegian School of Sport Sciences, Oslo, Norway, with at least 48 h between sessions (Fig. 1).

FIGURE 1.

Study design (R*, randomization).

We were able to recruit 51 women who fulfilled the inclusion criteria. Two were not able to attend the second test day, and two were excluded because of inability to perform correct PFM contractions. Data from the remaining 47 women were included in the data analysis. Participant characteristics are shown in Table 1. Among these, 15 were powerlifters, 14 were functional fitness exercisers, 14 were recreational exercisers, and 4 were Olympic weightlifters. Twenty-eight (59.6%) competed in their sport, and 13 (27.7%) were qualified to/had competed in national or international championship competitions. Most (n = 41; 87.2%) had completed or were current students of a higher level of education. Twelve (25.5%) reported chronic disease (irritable bowel syndrome, ulcerative colitis, endometriosis, vulvodynia, anemia, neurological disease, migraine, frequent herpes virus, and ovarian cysts). The prevalence of PFD is reported in Table 2.

TABLE 1.

Participant characteristics.

	Mean (SD, Min–Max)
Age, yr	27 (4.2, 19–34)
Height, cm	164 (6.7, 150–179)
Weight, kg	68.3 (9.3, 51.3–94.8)
BMI, kg·m−2	25.1 (2.9, 20–32.6)
Years of experience with strength training	7.4 (3.9, 1–17)
Hours of strength training per week	6.3 (2.7, 2–15)
Hours of other training per week	2.4 (1.9, 0–8)
1RM squat	108.1 (18.8, 71–180)
1RM deadlift	128.1 (19.6, 95–185)
Relative strength squat (1RM/bodyweight)	1.6 (0.2, 1.2–2.2)
Relative strength deadlift (1RM/bodyweight)	1.9 (0.3, 1.4–2.5)
PFM resting pressure, cm H2Oa	29.1 (6.1, 19.8–45.7)
PFM strengtha	24.7 (11.4, 6.3–58.1)
PFM endurancea,b	166.4 (82.1, 21–481)
PFM resting activity, mVa	12.5 (8.6, 0.5–36)

Mean with SD and minimum–maximum (min-max). N = 47.

^aValues of the first measurements on the test day are used.

^bN = 43.

BMI, body mass index.

TABLE 2.

Prevalence of reported pelvic floor dysfunctions (N = 47).

	n (%)
Any type of UI	22 (46.8)
SUI	19 (40.4)
AI
Liquid	10 (21.3)
Solid	3 (6.4)
Gas	29 (61.7)
POP	5 (10.6)

Procedures

The study was approved by the regional ethics committee (2018/2211/REK Sør-øst B, 20.12.2018) and the Norwegian Centre for Research Data (NSD: 199381, 24.01.2019). All subjects gave electronic and written informed consent before participation.

This was an experimental crossover study with random order of sessions. Informed consent, background variables (age, training exposure, chronic diseases), and reports of PFDs were collected using an electronic questionnaire (Survey Xact) 1–2 d before the baseline evaluation. To assess the prevalence of PFDs, we used patient-reported outcome measures recommended by the International Consultation on Incontinence (ICI) (17). For UI, we used the ICI Questionnaire–Urinary Incontinence Short Form. The ICI Questionnaire–Urinary Incontinence Short Form is easily completed and has shown to have acceptable convergent validity, ability to discriminate among different groups, and good reliability (Cronbach α of 0.95) (16). Women who responded “I leak when I am physically active” were considered to have SUI. To assess AI and symptomatic POP, we used questions from the ICI Questionnaire Anal Incontinence Symptoms and Quality of Life Module and ICI Questionnaire Vaginal Symptoms Module, respectively (17).

Day 1: Baseline evaluation

During the baseline visit, the participant’s weight and height were measured. After voiding, the participants were given a short lecture on functional anatomy of the pelvic floor. After that, a trained physiotherapist assessed the ability to contract the PFM by observation and vaginal palpation (15).

PFM resting activity was assessed by sEMG (15) with NeuroTrac MyoPlus Pro (Quintet, Bergen, Norway) and a 33-mm transverse diameter vaginal probe with two stainless steel lateral electrodes (35 × 15 mm; Periform; Quintet). The method has shown very good test–retest intrarater reliability for measurements of vaginal resting activity (intraclass correlation coefficient, 0.90; 95% confidence interval (CI), 0.84–0.94) (18). The PFM resting activity was calculated as the overall average microvolts recorded. PFM resting pressure, strength, and endurance were measured with a high-precision pressure transducer connected to a vaginal balloon catheter (Camtech AS, Oslo, Norway). The method has demonstrated good intraobserver reliability (18–22). The instructions were standardized, and we followed the same procedure as Bø et al. (20), Bø et al. (19), and Tennfjord et al. (22). The participants were instructed to perform three repetitions of maximum voluntary PFM contractions of approximately 3 s and one endurance PFM contraction of 10 s. PFM resting pressure was measured as the difference between the atmospheric pressure and the vaginal high-pressure zone at rest in cm H₂O (Fig. 2). PFM strength was calculated as the mean peak from the resting pressure line of three maximum voluntary contraction curves (cm H₂O), whereas PFM endurance was quantified as the area under the curve for 10 s (cm H₂O·s⁻¹; Fig. 2).

FIGURE 2.

Pressure curves from one participant including vaginal resting pressure, PFM strength (MVC 1–3), and muscular endurance.

Finally, 1-repetition maximum (1RM) tests were conducted for back squat and deadlift. The participants completed a warm-up including 5 min on an ergometer bike and 5 min of individual optional exercises. The 1RM protocol for back squat and deadlift was standardized, progressing from 10 repetitions at 20%, 4 repetitions at 55%, 3 repetitions at 65%, 2 repetitions at 75%, 1 repetition at 85%, and 1 repetition at 93%–95% of expected 1RM with 3-min rests between the warm-up sets and 5-min rests before and between the 1RM trials. Participants were allowed to use belts, shoes, or straps for lifting.

Day 2: Test day

The participants were randomized to start with 60 min of weightlifting or 60 min of rest (control period) with a washout period of 60 min before crossing over to the remaining session (Fig. 1). “A randomization list in blocks of 4 was computer-generated by an independent biostatistician using a random number generator. Allocation was concealed in sealed and opaque envelopes that were sequentially numbered. Randomization was unknown for the assessor and participant during the baseline evaluations and was revealed before the first session (weightlifting or rest) on the test day.” PFM measurements were performed immediately before/after the sessions and took approximately 15 min. The order of measurement was standardized (sEMG measurements of PFM resting activity followed by manometry measurements of PFM resting pressure, three maximum muscle forces (MVC), and 10-s sustained contraction). The participants were instructed to void before all measurements. We used test facilities that were placed in the same area to ensure time laps of <5 min between the sessions and measurements.

The weightlifting session included a 10-min warm-up (same as for the 1RM test), followed by four sets of four repetitions of back squat and deadlift at 75%–85% of 1RM. Three warm-up sets were included before the work sets (10 repetitions at 20%–30% of 1RM, 5 repetitions at 50%, and 3 repetitions at 70%). We used “repetitions in reserve” to assess perceived exertion between sets. The participants were asked to estimate how many repetitions remained before failure (23). A repetition in reserve score of 1–3 was considered acceptable, and a score closer to 1 was preferable for the last two sets. If necessary, adjustments to the load were made. Symptoms of PFD (e.g., urinary leakage, vaginal bulging) during the session were asked about and noted.

During the control session, the participants were allowed to read, work/study, or similar activities, but had to remain seated for the whole session (except for toilet visits).

Statistical analyses

Statistical analyses were performed in SPSS statistical software package version 28 (SPSS Inc., Chicago, IL). Background data were described by mean, SD, and minimum–maximum and prevalence of PFD with numbers and percentages. Histograms, box plots, and coefficient of skewness were used to check for normality. Differences in the changes of PFM variables within-group are reported as mean differences with 95% CI. The data of PFM resting activity, resting pressure, and strength were considered normally distributed. Paired t-tests were used to analyze within-group differences before and after weightlifting and rest, and to compare the changes from weightlifting versus rest. The PFM endurance data were not normally distributed, and Wilcoxon signed rank tests were used. Changes in PFM endurance were described by median and interquartile range (IQR). Endurance data from four participants were excluded from the analysis because of measurement errors. The P value was set to 0.05. To control for possible trends and systematic errors of the repeated PFM measurements on test day, box plots and spaghetti plots were constructed and evaluated by inspection by one of the researchers and a biostatistician. To assess whether the washout period was sufficient, we compared the mean change in prevalues of PFM strength and endurance between the participants who began with weightlifting and those who began with rest by independent-sample t-tests. The relationships between 1RM/relative strength (1RM/bodyweight) in back squat/deadlift and PFM strength were assessed by Pearson correlation coefficient. The first measurements of PFM strength from the test day were used. Preliminary analyses were performed to ensure normality, linearity, and homoscedasticity.

Power calculation

We performed a priori power calculation based on previous results from Ree et al. (24). A sample size of 42 was required to detect a pre–post difference in PFM strength of −4.4 cm H₂O (SD, 4.3) after resistance training and 0.6 cm H₂O (SD, 4.3) after rest with 80% power and a 5% significance level.

RESULTS

Table 3 shows manometry and sEMG measurements before and after heavy weightlifting and rest. There were small but statistically significant decreases in mean PFM resting activity on sEMG after both weightlifting and rest. When comparing the effect of heavy weightlifting with the effect of rest, we found no significant differences in change of PFM resting pressure (mean difference, 0.7 cm H₂O; 95% CI, −0.8 to 2.2), strength (mean difference, −1.6 cm H₂O; 95% CI, −5.1 to 1.8), endurance (median difference after exercise vs rest, 6 (IQR, −24.5 to 26.5) vs 13 (IQR, −15 to 40.2); P = 0.255) or resting activity (mean difference, 0.3; 95% CI, −0.9 to 0.5). We did not find any patterns/trends of the repeated PFM measures by inspection of box plots and spaghetti plots, and the risk of systematic errors, for example, learning effect, was considered low. There were no significant differences in mean change in prevalues of PFM strength (P = 0.705) and endurance (P = 0.295) between the participants who began with weightlifting and those who began with rest.

TABLE 3.

PFM measures: pre and post heavy weightlifting and rest.

	Heavy Weightlifting				Rest				Heavy Weightlifting vs Rest
	Pre	Post	Mean Difference	P	Pre	Post	Mean Difference	P	P
PFM resting pressure, cm H2O	29.1 (SD, 6.5)	28.2 (SD, 6.2)	0.9 (95% CI, −0.2 to 2.0)	0.096	30.3 (SD, 6.2)	30.1 (SD, 6.7)	0.2 (95% CI, −0.9 to 1.3)	0.715	0.349
PFM strength, cm H2O	23.4 (SD, 11.1)	23.7 (SD, 15.4)	−0.2 (95% CI, −2.5 to 2.1)	0.857	26.5 (SD, 15.4)	25.2 (SD, 16.8)	1.4 (95% CI, −1.3 to 4.2)	0.302	0.341
PFM enduranceb, cm H2O·s−1	164 (IQR, 105.8–206.3)c	134 (IQR, 88.0–218.0)c	N/A	0.876c	154 (IQR, 92.8–225.8)c	131 (IQR, 97.2–174.3)c	N/A	0.053c	0.225c
PFM resting activity, mV	10.8 (SD, 8.0)	9.2 (SD, 7.4)	1.6 (95% CI, 0.5–2.7)	0.005a	10.8 (SD, 8.5)	9.5 (SD, 8.0)	1.3 (95% CI, 0.4–2.1)	0.004a	0.614

N = 47. Data represented as mean and SD, mean difference and 95% CI, or median and IQR.

^aP < 0.005.

^bn = 4 values missing.

^cNonparametric test and Wilcoxon signed rank test reported with median and IQR.

N/A, not applicable.

Finally, no significant correlations between PFM strength and 1RM strength in back squat (r = 0.1; 95% CI, −0.19 to 0.38; P = 0.506) or deadlift (r = 0.08; 95% CI, −0.21 to 0.36; P = 0.58), or in relative strength (1RM/bodyweight) in back squat (r = 0.19; 95% CI, −0.10 to 0.45; P = 0.213) or deadlift (r = 0.18; 95% CI, −0.11 to 0.44; P = 0.226) were found.

DISCUSSION

To our knowledge, this is the first experimental study to investigate the effects of heavy weightlifting on the PFM. Abilities to produce MVC or to sustain muscle contractions are frequently used to assess levels of muscle fatigue/exhaustion after physical effort (25). Previous research indicates a relationship between PFM fatigue and the development and/or worsening of SUI (26). However, we found that a single session of heavy weightlifting did not affect PFM strength (MVC) or endurance (ability to sustain a PFM contraction for 10 s). Hence, the loads may be considered tolerable and below the intensity level to cause PFM fatigue in nulliparous, young, and strength-trained women.

We used sEMG and manometry to measure PFM resting tone, and no significant differences in change in PFM tone were found after weightlifting compared with rest. Muscle tone can be influenced by alterations in active (neural drive) or passive components (e.g., physical properties of muscle and connective tissue) (17). sEMG specifically measures the active electrogenic component of tone, whereas vaginal resting pressure measures the summative contribution of both active and passive components (17). We found small but significant decreases in PFM resting activity (sEMG) after both weightlifting and rest. This indicates a decrease in activated motor units, which can be interpreted as more relaxed muscles. However, the smallest detectable change with vaginal sEMG is previously reported to be 3.11 (18), and it should be questioned if the changes in our study of 1.6 after weightlifting and 1.3 after rest are clinically relevant. It has been suggested that strenuous training may cause nonrelaxing/hypertonic PFMs. This can potentially lead to pelvic pain, sexual disorders, and the inability to pass urine or stool (14). In our study, muscle tone did not increase after heavy weightlifting, and there is currently a lack of evidence to support these assumptions. Furthermore, well-established normative values and convincing evidence of an association of increased muscle tone with pain or other PFD are currently lacking (27). Therefore, measures of muscle tone should be interpreted carefully.

Altogether, our results suggest that heavy weightlifting at intensities of 75%–85% of 1RM can be considered PFM-safe for women who habitually lift heavy weights. However, PFD is highly prevalent in female strength athletes (10–12). Powerlifters often use rigorous training regimes with high specificity to improve their 1RM in back squats, bench presses, and deadlifts before competitions (28). Effects of heavy lifting greater than 85% of 1RM and long-term effects were not addressed in this study and should therefore be further investigated. Bø and Nygaard (9) suggest that there might be individual thresholds of intra-abdominal pressure related to possible harm or benefits of exercise on the pelvic floor. Individual variations in response to exercise were also observed in our study. Hence, strength athletes may experience PFD, such as urinary leakage, at different intensity levels. Female athletes/exercisers who experience PFD (e.g., SUI or pelvic pain) should be referred to a PFD specialist (e.g., urogynecologist or pelvic floor/women’s health physiotherapist) for early PFD management to ensure maintenance of exercise (29).

We found that strength in whole-body exercises was not correlated to PFM strength, which indicates that strength adaptions from heavy weightlifting exercises, such as back squats and deadlifts, are not specific to the PFMs. Consistent with our results, Moss et al. (30) found no associations between PFM strength and different measures of strength and fitness (e.g., hand grip strength) in postpartum women. Several studies have compared PFM strength in female athletes/exercisers and nonexercisers, but the results are conflicting across studies (9). Altogether, as many studies have confirmed that the prevalence of UI, AI, and POP is high in athletes, existing evidence does not support the assumption that general exercise can improve PFM strength and PFD (9). Evidence from randomized controlled trials, systematic reviews, and meta-analyses show that specific and targeted PFM strengthening training is necessary to improve PFM strength (31,32).

We were able to find two other experimental studies of the impact of exercise combinations on the pelvic floor. However, these differ in exercise type and participant characteristics, which may challenge the comparability of the results. Middlekauff et al. (33) assessed the immediate effect of a 25-min bout of strenuous exercise, including typical functional fitness exercises (push-ups, deadlift, push-press, burpees, and sit-ups) on PFM strength and resting pressure in nulliparous strenuous exercisers. Like our results, they found no significant changes in PFM strength but, on the contrary, a significant decrease in vaginal resting pressure. They also found an immediate and small, negative effect on vaginal support assessed by a standardized gynecological examination for staging POP called Pelvic Organ Prolapse Quantification. The PFM was assessed with a different vaginal pressure device, and the values are therefore not directly comparable to ours. Ree et al. (24) found that a 90-min bout of strenuous exercise (running and jumping activities, back squats, and lunges) led to a 20% decrease in PFM muscle strength, but no significant changes in vaginal resting pressure in nulliparous women with SUI. This study had a similar crossover design to ours and used the same (but older version) vaginal pressure device to measure the PFM. The pretest values of PFM strength and vaginal resting pressure are close to the pretest values found in our sample, implying a similar preconditioning of the PFM. However, Ree et al. (24) included only women with SUI, and the effect of exercise on the pelvic floor is likely different in women with incontinence compared with those without. In our study, we included both women with and without incontinence but unfortunately lacked statistical power to perform analyses between groups.

The exercise protocols in the aforementioned studies consisted of high-impact jumping and running activities in addition to weightlifting exercises, and loading characteristics of the pelvic floor may not be comparable to weightlifting alone. In a study of female functional fitness exercisers, intra-abdominal pressure curves showed higher and more sudden peak pressures during jumping activity compared with weightlifting activities (34). PFM response during weightlifting and exercise is, unfortunately, challenging to investigate because of a lack of good-quality in vivo measurement methods (8). Vaginal sEMG has been used in previous studies of PFM activity during running and jumping activities (35,36), but a movement of the vaginal probe and crosstalk from nearby muscles may potentially affect the outcomes (17). The validity of such measurements is therefore questioned.

Strengths and limitations

One strength of our study is the crossover design, which allowed each participant to serve as her own control. The order of intervention was randomized. The advantages of this design are that the risk of intersubject variability and the risk of confounding are minimized (37). The number of participants was based on an a priori power calculation, all participants had experience with heavy weightlifting and were able to follow the test protocol as planned. Training experience in our sample allowed for heavy loads during weightlifting, and 1RM strength tests provided accurate measures of training intensity and muscular strength. The PFM measurement methods used are reliable and valid (18–20,22). The testing procedure was standardized and performed by the same examiner, which ensured consistency throughout the data collection.

The washout period between sessions and randomizing of the order of sessions may have minimized the risk of carryover effects. Häkkinen (38) found that maximum knee extension force recovered to approximately 90% of the preexercise force in females 1 h after exercise. If we assume an indirect loading of the PFM of moderate intensity during the weightlifting session, a 1-h washout should be sufficient to restore maximum voluntary contraction force. However, because of a lack of supporting literature on fatigue and recovery of PFM force development, we cannot completely assure this. Changes in the prevalues of PFM strength and endurance were not significantly different between those who performed the weightlifting session first and those who started with rest, implying a sufficient washout period to restore PFM force and endurance.

Unfortunately, our sample was not powered to analyze differences in response to weightlifting between women with and without SUI. Furthermore, the assessor of PFM variables was not blinded to the order of the sessions. This was mainly due to testing logistics and a lack of resources. Wide CI values imply individual variation in results. Because our participants had no or little experience with assessments of the PFM, we cannot rule out that individual improvement of PFM strength could be a result of a learning effect. However, the purpose of baseline PFM measurements was to have the participants familiarized with the tests and minimize the learning effect on the test day. We lack information about the participants reproductive profiles (menstrual status/cycle/irregularities, use of contraceptives or hormonal therapy). However, we do not believe that our results were influenced by differences in reproductive profiles and variations in menstrual cycle, because the participants served as their own control and the PFM measurements were performed on the same day. Furthermore, measurements of contraction time and force parameters have previously been found to be stable during different phases of the menstrual cycle (39). Finally, our study sample may have been too homogeneous regarding genetic factors, training experience, and strength levels to detect linear relationships between whole-body strength and PFM strength.

Long-term effects on the PFM and risks of developing PFD were not addressed in this study and should be further investigated. It is also possible that weightlifting at higher intensities (≥90% of 1RM) may have a larger effect on the PFM. Furthermore, PFD has been reported as a common barrier to exercise among women (40). Our sample consisted of women who persisted with strength training (not those who stopped lifting weights because of PFD), which may be a result of a natural selection of women who tolerate weightlifting with high loads well.

Clinical implications

Although heavy weightlifting exercises (e.g., back squat and deadlift) are assumed to produce strain on the pelvic floor, our results imply that these exercises are well tolerated by the PFM in healthy, nulliparous strength-trained women. Heavy weightlifting did not affect levels of exhaustion or muscle tone in our sample. However, the effect may be different among women with a higher risk of PFD, such as parous, postpartum, or older (>35 yr) women. Our findings suggest that heavy weightlifting at 75%–85% of 1RM has limited effects on levels of fatigue and muscle tone in strength-trained women. Because PFD is common among female powerlifters and Olympic weightlifters, the long-term effects of heavy weightlifting and lifting greater than 85% of 1RM should be further investigated. Furthermore, individual PFM tolerance to training loads may vary, and PFD in strength athletes is important to address to identify relevant treatment options. Finally, our results show that whole-body strength is not associated with stronger PFM. Studies assessing the effect of targeted PFM training in strength athletes are therefore warranted—especially for women with SUI or other PFD.

CONCLUSIONS

We found no immediate effect on the PFM by heavy weightlifting (back squat and deadlift of 75%–85% of 1RM) compared with rest in strength-trained, nulliparous women. Furthermore, there was no correlation between strength in back squat/deadlift and PFM strength.