Abstract
ackground:Weightlifters commonly use upper-extremity high-load training, which en- compasses techniques ranging from momentary failure to non-failure. However, little is known about how this training affects posture and core endurance, despite knowing that these factors are risk factors for weightlifting injuries. Therefore, this study aimed to determine the immediate effects of upper-extremity high-load training to momentary failure versus non-failure, using the dumbbell overhead press, on posture and core en- durance in recreational collegiate weightlifters.Methods:Fifty recreational weightlifters aged 18–24 with two years of upper extremity resistance training experience were recruited for this study. The participants performed dumbbell overhead press exercises under high- load failure (HL-F) and high-load non-failure (HL-NF) conditions two days after 1RM testing and calculation of the 80% 1RM load. The study analyzed postural changes using photographic data processed in Kinovea, while core endurance was assessed during a prone plank test. Standardized warm-ups, controlled exercise execution, and pre- and post- exercise
The participants performed dumbbell overhead press exercises under high- load failure (HL-F) and high-load non-failure (HL-NF) conditions two days after 1RM testing and calculation of the 80% 1RM load. The study analyzed postural changes using photographic data processed in Kinovea, while core endurance was assessed during a prone plank test. Standardized warm-ups, controlled exercise execution, and pre- and post- exercise assessments were conducted to measure core endurance and postural alterations. Results:The thoracic kyphosis angle, together with scapular balance angle and lateral scapular slide distance, increased significantly after HL-F compared to the unloading state, while the craniovertebral angle and prone plank time decreased significantly (p< 0.05). The HL-NF condition showed no statistically significant differences relative to the unloading measurements (p> 0.05). The unloading measurements across testing days were consistent, indicating no carryover effect (p> 0.05).Conclusions:The findings indicate that high-load training to failure adversely affects posture and core endurance, increasing fatigue and potentially increasing the risk of acute injuries. Non-failure training maintains stability, un- derscoring the importance of strategic program design for achieving optimal performance while minimizing adverse effects. J. Clin. Med.2026,15, 2815 https://doi.org/10.3390/jcm15082815
J. Clin. Med.2026,15, 2815 2 of 13 Keywords:core endurance; high-load training; muscle failure; upper extremity; collegiate weightlifters 1. Introduction Weightlifting is a widely practiced activity aimed at increasing strength and achiev- ing muscle hypertrophy through repeated muscle actions against progressive resistance, exceeding the demands of daily activities [1]. In recent years, weightlifting has gained substantial popularity as a recreational activity, with college students representing nearly 35% of participants [2,3]. For those young adults, weightlifting improves both physical appearance and mental well-being. It boosts self-esteem, fosters a sense of control, and helps counter societal pressures, promoting a healthier and more confident self-image [4]. Despite its benefits, weightlifting carries a significant risk of injury, particularly when performed incorrectly [2]. Over a six-year period, the annual incidence of weightlifting- related injuries increased from 86,910 to 109,961, with nearly 40% involving the shoulder and upper trunk [5]. Common risk factors include sudden weight drops due to loss of balance and improper technique linked to poor body alignment [6]. These injuries underscore the importance of proper form and core stability during weightlifting. The core musculature is essential for stabilizing the trunk and maintaining proper posture during dynamic movements, playing a critical role in power generation and enhancing overall movement efficiency [7]. Research has extensively explored key training variables, such as load intensity, rep- etitions, and sets, which collectively define training volume [8–10]. Traditional weight training typically associates strength gains with high-load (HL) lifting, but previous stud- ies have shown inconsistencies in defining HL based on one-repetition maximum (1RM) percentages. Early studies defined high-load (HL) training as loads exceeding 60% [11] or 70% [12] of the one-repetition maximum (1RM). However, a recent systematic review and meta-analysis established a more precise criterion, defining HL as≥80% of the 1RM [13]. Moreover, a growing belief in weightlifting suggests that training into momentary muscle failure optimizes neuromuscular gains when a muscle cannot complete another concentric repetition. This principle has driven much of the earlier research on training to failure [14–16]. However, recent studies challenge this notion, demonstrating that training to failure is comparable to non-failure training for enhancing muscle hypertrophy,
1RM [13]. Moreover, a growing belief in weightlifting suggests that training into momentary muscle failure optimizes neuromuscular gains when a muscle cannot complete another concentric repetition. This principle has driven much of the earlier research on training to failure [14–16]. However, recent studies challenge this notion, demonstrating that training to failure is comparable to non-failure training for enhancing muscle hypertrophy, strength, and architecture [17,18]. These findings suggest that alternative approaches may be equally effective without the added strain of pushing to failure. In weightlifting sports, pressing motions such as an overhead press are key for engag- ing the upper quarter muscles [19]. The overhead press, also known as the shoulder or military press, is a compound exercise that involves the hands, arms, and shoulder girdle muscles [20]. Given the importance of core stabilization in preventing injuries, pressing exercises, particularly the dumbbell overhead press, are known for their high stabilization demands [21,22]. Despite extensive research on load intensity and training to failure in relation to strength, motor unit recruitment, and hypertrophy, no prior studies have explored its effects on body alignment and core endurance. Addressing this gap is essential, as it provides valuable insights for recreational lifters seeking to optimize training strategies, enhance performance, and reduce injury risk. Therefore, this study investigated the acute effects of upper-extremity high-load training to failure (HL-F) versus non-failure (HL-NF) using the dumbbell overhead press on posture and core endurance in collegiate weightlifters. https://doi.org/10.3390/jcm15082815
J. Clin. Med.2026,15, 2815 3 of 13 2. Materials and Methods 2.1. Study Design This within-subject crossover study was conducted in the college physiotherapy lab between February 2024 and October 2024. The ethical committee of Batterjee Medical College (RES-2024-0217) reviewed and approved the study procedures in compliance with the most recent version of the Declaration of Helsinki. All participants provided written informed consent after receiving a detailed explanation of the study objectives and their right to withdraw without consequences. 2.2. Sample Size G*POWER statistical software (version 3.1.9.3; Universität Düsseldorf, Düsseldorf, Germany) was utilized to determine the required sample size for the study. A total sample size of 45 weightlifters was accepted based on an alpha of 0.05, a power of 80%, and a medium effect size of 0.50 [18]. An unpublished pilot study on 12 weightlifters further supported the reported effect size. 2.3. Participants This study included 50 recreational weightlifters (28 males, 22 females; body mass: 84.2±8.1 kg; height: 175.3±4.6 cm; BMI: 26.8±1.4 kg/m 2 ) aged 18–24 years. These participants were recruited through hanging posters, distributing flyers, and sending mass emails. To qualify as resistance-trained for the study, participants must engage in upper extremity resistance weight training twice a week, at an intensity that reaches 80% of the 1RM, with an average of four sets per training session and seven to nine repetitions. The lifting experience should be at least two years before the start of the study [23]. Weightlifters who used hormonal supplements, participated in professional powerlift- ing or bodybuilding events, had shoulder pain, previous musculoskeletal injuries, or missed more than three weeks of lifting workouts over the last six months wereexcluded [3] . All inclusion and exclusion criteria were assessed through a standardized screening ques- tionnaire and personal interview conducted by trained research assistants. A total of 62 weightlifterswere initially assessed for eligibility; however, 12 were excluded for failing to meet the specified inclusion criteria. A within-subject crossover design was used to include all participants in a single group to maximize homogeneity and reduce between-subject variances resulting from physical, strength, and training level characteristics [24]. The study
personal interview conducted by trained research assistants. A total of 62 weightlifterswere initially assessed for eligibility; however, 12 were excluded for failing to meet the specified inclusion criteria. A within-subject crossover design was used to include all participants in a single group to maximize homogeneity and reduce between-subject variances resulting from physical, strength, and training level characteristics [24]. The study flowchart is shown on Figure. 2.4. Procedures 2.4.1. One-Repetition Maximum (1RM) Testing At first, the weightlifter attended the college physiotherapy lab for 1RM familiarization and determination. The testing procedure was by the National Strength and Conditioning Association recommendations [25]. The session began with 10 min of low-intensity general and specific warm-up exercises. These included 5 min of treadmill walking at a normal pace, clockwise and counterclockwise arm circular movements, and overhead press with light weight. The weightlifter was then given a detailed explanation of correctly performing the overhead press exercise. Participants were instructed to stand with their feet positioned shoulder-width apart, holding dumbbells at shoulder level with their palms facing forward and elbows positioned slightly ahead of the torso. They were told to engage the core, keep the neutral spine, and press the weight overhead in a straight line until the arms were fully extended without locking the elbows. The emphasis was on preventing excessive lower https://doi.org/10.3390/jcm15082815
J. Clin. Med.2026,15, 2815 4 of 13 back arching by keeping the ribcage down and the gluteus and core active for stability. They were also told to lower the weight in a controlled manner to the starting position while keeping their wrists in line with their forearms. This instruction form was adopted from the NCSA manual guidelines [26]. Figure 1.The study flowchart. The researcher observed the exercise form during the testing trial, which ended when the performance technique was deviated. The first lifting load was set according to the weight that each participant stated as their failure point after one repetition. This first weight was then gradually increased until the actual 1RM was obtained, and no more than five trials were done daily. A two-minute rest interval was set between the tests to ensure that the results of the tests would not be affected by fatigue [27]. The 1RM was retested after 72 h to ensure reliability. If the difference between the first and second tests was more than 5%, the procedures were repeated after another 72 h [13,15]. Only 12 participants required three trials to determine the 1RM. For each participant, 80% of the 1RM was calculated and recorded to be used in the high-load testing condition [13]. 2.4.2. Testing Protocol Before the testing session, participants were informed about the criteria for momentary muscular failure, defined as the point at which they could no longer perform an additional https://doi.org/10.3390/jcm15082815
J. Clin. Med.2026,15, 2815 5 of 13 repetition with correct technique. In contrast, during training to non-failure, participants voluntarily stopped their repetitions based on their perceived fatigue, halting three to four repetitions (Reps in Reserve) short of reaching the point of muscular failure [18]. In addition to the day designated for 1RM determination, each weightlifter partici- pated on two testing days, depending on whether failure was reached. A 72 h recovery period was provided between testing days to prevent fatigue or carryover effects [13]. Testing was conducted at the same time of day to minimize circadian effects, and the order of days was randomized using a random number generator. Every testing day typically began with warming up similar to the routine used during the determination of the 1RM, followed by capturing the overhead press exercise in its unloaded state, which involved performing the exercise without holding any weight [28]. The number of sets performed before measuring the outcomes depended on each participant’s usual lateral raise training routine. This personalized approach was se- lected to replicate real training conditions. Typically, participants completed 3–5 sets (mean = 4.1±0.8 sets ) of overhead press at 80% 1RM, with 2 min rest intervals, prior to post-exercise assessments [29]. 2.5. Outcome Measures 2.5.1. Photographic Postural Analysis Two digital cameras (Canon Inc., Tokyo, Japan, model EOS 750D) were used to capture lateral and posterior views of each participant. Photographic analysis of the upper quarter posture from sagittal and posteroanterior perspectives was conducted. Postural analysis was conducted using Kinovea software (version 0.9.5), which is a valid and reliable tool that can measure accurately at distances of up to 5 m from the subject [30]. Participants were instructed to assume and maintain their regular standing posture typically used during exercise routines, to ensure consistency in biomechanical alignment. The camera, placed on a tripod, was positioned 2 m away from the participants, with its height adjusted to align with the external auditory meatus in the sagittal plane and the skull’s greatest protrusion in the frontal plane [31]. The final set of exercises on each day involved recording a video
during exercise routines, to ensure consistency in biomechanical alignment. The camera, placed on a tripod, was positioned 2 m away from the participants, with its height adjusted to align with the external auditory meatus in the sagittal plane and the skull’s greatest protrusion in the frontal plane [31]. The final set of exercises on each day involved recording a video and analyzing the image of the final set repetition. Independent physical therapists, blinded to the study purpose, performed photographic analyses. These therapists were well-trained and had prior experience in conducting photographic postural analysis, ensuring interrater reliability and consistency in the measurements. Four measurements, two from each recording plane, were analyzed as follows: the craniovertebral angle and the thoracic kyphosis angle were measured from the sagittal plane. The craniovertebral angle is formed by the intersection of a line drawn from the tragus of the ear to the horizontal line through the spinous process of C7. The thoracic kyphosis angle is formed at the intersection of two lines passing through T12 and C7 (sagittal view—FigureA) [ 32]. A craniovertebral angle (CVA) of less than 48 degrees is defined as forward head posture, whereas a thoracic kyphosis angle greater than 40 degrees is considered hyperkyphosis [33]. Moreover, from the anteroposterior view, the scapular balance angle was calculated by determining the angular difference between a line connecting the inferior angles of both scapulae and a vertical reference line aligned with the spinal column [23]. Additionally, the lateral scapular shift distance was measured from the scapulae’s inferior angle to the thoracic vertebrae’s spinous process at the same level (FigureB) [ 34]. Asymmetry in the position of the scapulae or scapular dyskinesis is defined as a difference between the two sides of the body of more than 7 degrees in the scapular angle or more than 1.5 cm in the lateral shift distance [35]. Postural analysis used a single photographic frame from the final repetition of the final set, representing maximal fatigue, and was analyzed by independent, https://doi.org/10.3390/jcm15082815
than 7 degrees in the scapular angle or more than 1.5 cm in the lateral shift distance [35]. Postural analysis used a single photographic frame from the final repetition of the final set, representing maximal fatigue, and was analyzed by independent, https://doi.org/10.3390/jcm15082815
J. Clin. Med.2026,15, 2815 6 of 13 blinded therapists using Kinovea software (v.0.9.5). No averaging across repetitions was conducted. Figure 2.Measurement of craniovertebral angle, thoracic kyphosis angle (A), scapular balance angle, and the lateral scapular shift distance (B). 2.5.2. Prone Plank Time The endurance prone plank test is widely recognized as a valid, reliable, and practical tool for assessing overall core muscle endurance, especially in athletes who have had at least one familiarization session beforehand [36,37]. To begin the test, participants got into the standard plank position, lying face down, supported on their forearms and toes. Their elbows were aligned directly under their shoulders, with forearms and hands extended forward. The test assessor instructed participants to maintain a straight body from head to heels. The test was ended immediately when participants could not maintain the neutral plank position despite verbal cueing (a straight head-to-heels posture without pelvic sagging, hip piking, or repositioning of the forearms or feet), and at that point, the time was recorded as plank endurance [38]. 2.6. Statistical Analysis The data were analyzed using the Statistical Package for Social Sciences version 20 (SPSS Inc., Chicago, IL, USA). The data were tested for normality and homogeneity of variance assumptions before the final analysis. The data’s homogeneity and normal distribution were confirmed by the Shapiro–Wilk test and Levene’s test (p> 0.05). This exploration was conducted as a prerequisite for parametric variance analysis. Repeated- measures ANOVA was used to assess the effect of upper-extremity HL-F versus HL- NF training on upper-body quarter posture and core endurance. A Bonferroni-adjusted post hoc test was used to identify the source of significant differences, providing a more conservative control of the family-wise Type I error rate. The significance level was set at 0.05 for all statistical tests. 3. Results Through HL-F training, the value of CVA and prone plank time during unloading conditions was significantly greater than those during the loading condition (p= 0.003 and 0.002, respectively). In contrast, the values of the thoracic kyphosis angle, scapular balance https://doi.org/10.3390/jcm15082815
all statistical tests. 3. Results Through HL-F training, the value of CVA and prone plank time during unloading conditions was significantly greater than those during the loading condition (p= 0.003 and 0.002, respectively). In contrast, the values of the thoracic kyphosis angle, scapular balance https://doi.org/10.3390/jcm15082815
Description
The study evaluates the effects of high-load training on posture and core endurance.