Changes in Muscle Mass and Strength in Adolescents Following High-Intensity Functional Training with Bodyweight Resistance Exercises in Physical Education Lessons.

(1) Background: The growing prevalence of obesity, diabetes, hypertension, and declining physical fitness among children and adolescents due to sedentary lifestyles has increased attention toward preventive intervention to tackle this issue. This study investigated the age-related effects of high-intensity functional training (HIFT), based on bodyweight resistance exercises conducted during physical education lessons, on muscle mass and strength improvement. (2) Methods: Adolescent males (n = 116) were allocated to four HIFT experimental groups (EGs) and four standard physical education program control groups (CGs) according to age (15, 16, 17, and 18 years [y]). The changes in muscle mass (absolute and relative to height [SMI]), hand-grip strength (HGS), sit-ups (SUs), and standing broad jump (SBJ) were analyzed using two-way analysis of variance (ANOVA) with Bonferroni tests. (3) Results: HIFT significantly increased muscle mass and scores in all strength tests (p < 0.01), while chronological age was significant for HGS (p < 0.01). Interactions between HIFT and chronological age categories were observed for HGS (p = 0.01) and SBJ (p < 0.03). Detailed post hoc tests revealed improvement in muscle mass across all chronological age categories for both approaches (p < 0.05). The 18y-EG group improved HGS over their control peers (p < 0.01), the EG groups significantly improved their SU results (p < 0.01), and SBJ improved in the 15y-EG and 18y-EG groups compared to their control (p < 0.01). (4) Conclusions: This research highlights the effectiveness of a school-based HIFT program in promoting muscle mass gains and enhancing muscle strength among adolescents. The findings offer valuable insights for implementing bodyweight exercises during physical education classes.

Effects of Short-Term Core Stability Training on Dynamic Balance and Trunk Muscle Endurance in Novice Olympic Weightlifters.

Our primary objective was to investigate the effects of short-term core stability training on dynamic balance and trunk muscle endurance in novice weightlifters learning the technique of the Olympic lifts. Our secondary objective was to compare dynamic balance and trunk muscle endurance between novice and experienced weightlifters. Thirty novice (NOV) and five experienced (EXP) weightlifters participated in the study. Mediolateral (ML) and anteroposterior (AP) dynamic balance and trunk muscle endurance testing were performed a week before (Pre) and after (Post) a 4-week core stability training program. In the NOV group, there was an improvement of both dynamic balance (ML and AP, p = 0.0002) and trunk muscle endurance (p = 0.0002). In the EXP group, there was no significant difference between Pre and Post testing conditions, except an increase in muscle endurance in the right-side plank (p = 0.0486). Analysis of the results showed that experienced lifters were characterized by more effective dynamic balance and greater core muscle endurance than their novice peers, not only before the training program but after its completion as well. In conclusion, the applied short-term core stability training improved dynamic balance and trunk muscle endurance in novice weightlifters learning the Olympic lifts. Such an exercise program can be incorporated into a training regime of novice weightlifters to prepare them for technically difficult tasks of the Olympic snatch and clean and jerk.

Effects of High-Velocity Strength Training on Movement Velocity and Strength Endurance in Experienced Powerlifters with Cerebral Palsy.

The present study aimed to evaluate the effects of a 6-week high-velocity strength training (HVST) intervention on movement velocity and strength endurance in experienced powerlifters with cerebral palsy (CP). Eleven experienced powerlifters with CP and seven from a control group (CON), were subjected to 6-week HVST. An assessment of movement velocity and strength endurance was conducted one week before (T1) and one week after (T2) the 6-week training intervention. During testing, athletes performed a maximum number of bench press repetitions possible within 5 sets of 15 s each, with 1-min passive rest intervals in-between. The indicator of movement velocity was the weight pressed in the first 5 s (5sW) in all performed sets. Strength endurance was described by the total weight (TW) pressed during the test. 5sW in T2 was significantly higher as compared with T1 in the CP group only (T1 928.9 ± 342.9 kg vs. T2 1007.3 ± 324.6 kg; p = 0.016). TW in T2 was significantly higher as compared with T1, both in the CP group (T1 2550.5 ± 843.9 kg vs. T2 2809.8 ± 981.3 kg; p < 0.001) and in the CON group (T1 2300.7 ± 845.1 kg vs. T2 2468.9 ± 890.1 kg; p = 0.049). A 6-week program of HVST increased movement velocity in resistance trained CP athletes. The gains of strength endurance were observed in both groups.

Acute effects of contract-relax proprioceptive neuromuscular facilitation stretching of hip abductors and adductors on dynamic balance.

BACKGROUND: Balance control has been shown to play a fundamental role both in everyday life and many athletic activities. An important component of balance control is the somatosensory information gained from muscle spindles and Golgi tendon organs. The changes in the muscle-tendon unit stiffness could alter the ability to detect and respond promptly to changes of an unstable environment. One of the procedures affecting muscle stiffness is stretching, and contract-relax PNF stretching (CRS) is considered as one of the safest and most effective techniques. So far, there are no studies on the impact of CRS of hip adductor and abductor muscles on body balance. These muscle groups are responsible for maintaining mediolateral balance which is of particular interest, since it is more affected by ageing and disease and since its deterioration has been associated with an increased risk of falling. In light of the above, the aim of the present study was to investigate the effects of a single dose of contract-relax proprioceptive neuromuscular facilitation stretching of hip adductors and abductors on mediolateral dynamic balance. METHODS: The study involved 45 healthy individuals (age 19-23 years) assigned to the intervention group (IG) or the control group (CG). Balance testing was carried out before (Pre) and immediately after CRS in the intervention group or after 5-minute rest in the control group (Post). There were performed three repetitions of the CRS targeting the adductor and abductor muscles of the hip. RESULTS: Statistically significant differences between Pre and Post condition were observed only in the intervention group. The values of all measured variables defining the body's dynamic balance were significantly lower immediately after the applied CRS, which indicates an improved body balance: Global Index (p = 0.0001), total area of sway (p = 0.0001), external area of sway (p = 0.00004), external time (p = 0.0004) and reaction time (p = 0.0003). CONCLUSIONS: A single dose of contract-relax proprioceptive neuromuscular facilitation stretching of the hip adductor and abductor muscles improved mediolateral dynamic balance.

Acute effects of core stability exercises on balance control.

PURPOSE: The aim of this study was to investigate whether a single bout of core stability exercises improves body balance immediately after the bout of exercise and during a retention test. METHODS: The study involved 16 women (age 22-25 years, body weight 60.5 ± 5.2 kg, height 166 ± 5.4 cm). Postural stability was assessed in the mediolateral (ML) and anteroposterior (AP) planes separately on a force plate (Kistler 9286 AA) during quiet standing on a soft support surface with the eyes closed. Subjects were measured 4 times: just before (T0), 1 minutes after (T1 m), 30 minutes after (T30 m), and 24 hours after the workout (T24 h). Postural balance was evaluated by five parameters based on the center of pressure (COP) signal: variability (VAR), mean velocity (VEL), sample entropy (ENT), frequency (FRE), and fractal dimension (FRA). RESULTS: We observed a decrease in VAR and VEL in the ML plane at T30 m and T24 h, compared to T0. The COP entropy significantly increased in the ML plane at T24 h, compared to T0. CONCLUSIONS: A single bout of core stability exercises improved the control of the mediolateral body balance. This effect was evident within 30 minutes after exercise, and remained for at least 24 hours. In addition, 24 hours after exercise we observed an increased automaticity in the strategy to maintain a stable upright stance.

Changes in Muscle Stiffness of the Trapezius Muscle After Application of Ischemic Compression into Myofascial Trigger Points in Professional Basketball Players.

The study aimed to assess the effects of compression trigger point therapy on the stiffness of the trapezius muscle in professional basketball players (Part A), and the reliability of the MyotonPRO device in clinical evaluation of athletes (Part B). Twelve professional basketball players participated in Part A of the study (mean age: 19.8 ± 2.4 years, body height 197 ± 8.2 cm, body mass: 91.8 ± 11.8 kg), with unilateral neck or shoulder pain at the dominant side. Part B tested twelve right-handed male athletes (mean ± SD; age: 20.4 ± 1.2 years; body height: 178.6 ± 7.7 cm; body mass: 73.2 ± 12.6 kg). Stiffness measurements were obtained directly before and after a single session trigger point compression therapy. Measurements were performed bilaterally over 5 points covering the trapezius muscle. The effects were evaluated using a full-factorial repeated measure ANOVA and the Bonferroni post-hoc test for equal variance. A p-value < .05 was considered significant. The RM ANOVA revealed a significant decrease in muscle stiffness for the upper trapezius muscle. Specifically, muscle stiffness decreased from 243.7 ± 30.5 to 215.0 ± 48.5 N/m (11.8%), (p = .008) (Part A). The test-retest relative reliability of trapezius muscle stiffness was found to be high (ICC from 0.821 to 0.913 for measurement points). The average SEM was 23.59 N/m and the MDC 65.34 N/m, respectively (Part B). The present study showed that a single session of compression trigger point therapy can be used to significantly decrease the stiffness of the upper trapezius among professional basketball players.

[The impact of group therapeutic exercises on postural stability and the risk of falls of postmenopausal women]. / Wplyw gimnastyki ogólnousprawniajacej na stabilnosc posturalna i ryzyko upadków kobiet po okresie menopauzalnym.

INTRODUCTION: In the elderly, balance control in dynamic situations is often disrupted due to postural instability, leading to an increased risk of falls. Regressive changes are observed fastest in the free movements. As a result of the aging of the central nervous system is reduced precision, the pace of the independent precise movement and proprioception in the joints. Concentration and reaction time also deteriorate. It is considered that falls are one of the causes of loss of performance in the elderly. THE AIM: The impact assessment of group therapeutic exercises on the efficiency of gait, the 'ability to' maintain the balance and the degree of the risk of falls in people over 55 years of age. MATERIAL AND METHODS: The tested group were women aged 56-80 years old, physically active, participating in group therapeutic exercises. To the control group were assigned women in a similar age group, physically inactive. RESULTS: The research revealed the presence of significantly lower the risk of falls in physically active people. CONCLUSIONS: Physically inactive people have a worse balance and gait than physically active people.

[The dependence of muscle strength in the shoulder rotators on the shoulder abduction angle]. / Zaleznosc sily miesni rotujacych ramie od wartosci kata odwiedzenia ramienia.

Background. The shoulder joint has a very complex structure. Normal shoulder function is dependent on joint stability and proper neuromuscular control. Given its anatomical structure and range of movement, this joint is highly susceptible to numerous disorders and injuries. Normal stability of the shoulder guarantees physiological function, and is also the most important element of injury prevention. Disturbances of the strength and reciprocal proportions of the inner and outer rotator muscles, as well as the shoulder abductors, can be a mechanism leading to shoulder instability. The goal of our study was to evaluate the muscle strength of the shoulder rotators in terms of the abduction angle in healthy individuals. Material and methods. We examined 100 healthy volunteers (200 shoulders), 50 men and 50 women. Each subject enrolled in the study performed 32 measurements of muscle strength in the shoulder rotators, for a grand total of 3200 measurements, performed in alternation (outward and inward rotation) at various angles of shoulder abduction. Results. The strength of the muscles responsible for inward and outward rotation in persons without shoulder injury rose along with shoulder abduction, from 0 degrees to 70 degrees . When the shoulder was abducted to 70 degrees , the strength of the inner rotators was the highest, significantly higher than that of the outer rotators. When the shoulder was abducted to 90 degrees , there was relative equilibrium of muscle strength (N) between the inner and outer rotators. Conclusions. 1. Muscle strength in the outer and inner shoulder rotators in healthy individuals was dependent on the abduction angle. 2. The overall strength was higher in the men than in the women, but there were no significant differences in the direction of changes in strength at various angles of abduction. 3. The results obtained here in persons without shoulder injury can serve as norms for evaluating progress in physiotherapy in 20-30-year-old patients with shoulder injuries.