Marília dos Santos Andrade

Isokinetic hamstrings-to-quadriceps peak torque ratio: The influence of sport modality, gender, and angular velocity

Abstract The purpose of this study was to determine differences in hamstrings-to-quadriceps (H/Q) peak torque ratios evaluated at different angular velocities between men and women who participate in judo, handball or soccer. A total of 166 athletes, including 58 judokas (26 females and 32 males), 39 handball players (22 females and 17 males), and 69 soccer players (17 females and 52 males), were evaluated using an isokinetic dynamometer. The H/Q isokinetic peak torque ratios were calculated at angular velocities of 1.05 rad · s−1 and 5.23 rad · s−1. In the analysis by gender, female soccer players produced lower H/Q peak torque ratios at 1.05 rad · s−1 than males involved in the same sport. However, when H/Q peak torque ratio was assessed at 5.23 rad · s−1, there were no significant differences between the sexes. In the analysis by sport, there were no differences among females at 1.05 rad · s−1. In contrast, male soccer players had significantly higher H/Q peak torque ratios than judokas (66 ± 12% vs. 57 ± 14%, respectively). Female handball players produced significantly lower peak torque ratios at 5.23 rad · s−1 than judokas or soccer players, whereas males presented no ratio differences among sports At 5.23 rad · s−1. In the analysis by velocity, womens muscular ratios assessed at 1.05 rad · s−1 were significantly lower than at 5.23 rad · s−1 for all sports; among men, only judokas presented lower ratios at 1.05 rad · s−1 than at 5.23 rad · s−1. The present results suggest that sport modality and angular velocity influence the isokinetic strength profiles of men and women.

Shoulder functional ratio in elite junior tennis players

OBJECTIVE To evaluate shoulder rotation strength and compare the functional ratio between shoulders of elite junior tennis players. DESIGN This cross-sectional study evaluated muscular rotation performance of 40 junior tennis players (26 male and 14 female) with an isokinetic dynamometer. MAIN OUTCOME MEASURES Strength variables of external (ER) and internal rotators (IR) in concentric and eccentric modes were considered. For the peak torque functional ratio, the eccentric strength of the ER and the concentric strength of the IR were calculated. RESULTS All variables related to IR were significantly higher on the dominant compared to the non-dominant side in males and females (p<0.05), but only boys exhibited this dominance effect in ER (p<0.05 and p<0.001). Regarding functional ratios, they were significantly lower for the dominant shoulder (p<0.001) and below 1.00 for both groups, indicating that the eccentric strength of the ER was not greater than the concentric strength of the IR. CONCLUSION Elite junior tennis players without shoulder injury have shoulder rotation muscle strength imbalances that alter the normal functional ratio between rotator cuff muscles. Although these differences do not seem to affect the athletic performance, detection and prevention with exercise programs at an early age are recommended.

Acute strength exercise and the involvement of small or large muscle mass on plasma brain-derived neurotrophic factor levels

OBJECTIVE: Blood neurotrophins, such as the brain‐derived neurotrophic factor, are considered to be of great importance in mediating the benefits of physical exercise. In this study, the effect of acute strength exercise and the involvement of small versus large muscle mass on the levels of plasma brain‐derived neurotrophic factor were evaluated in healthy individuals. METHODS: The concentric strengths of knee (large) and elbow (small) flexor and extensor muscles were measured on two separate days. Venous blood samples were obtained from 16 healthy subjects before and after exercise. RESULTS: The levels of brain‐derived neurotrophic factor in the plasma did not significantly increase after both arm and leg exercise. There was no significant difference in the plasma levels of the brain‐derived neurotrophic factor in the arms and legs. CONCLUSION: The present results demonstrate that acute strength exercise does not induce significant alterations in the levels of brain‐derived neurotrophic factor plasma concentrations in healthy individuals. Considering that its levels may be affected by various factors, such as exercise, these findings suggest that the type of exercise program may be a decisive factor in altering peripheral brain‐derived neurotrophic factor.

Profile of isokinetic eccentric-to-concentric strength ratios of shoulder rotator muscles in elite female team handball players

Abstract The purpose of this study was to establish the isokinetic profile of shoulder rotator muscles strength in female handball players. Twenty-seven handball players performed concentric and eccentric strength tests of both dominant and non-dominant upper limbs on an isokinetic dynamometer. Internal and external rotator muscles peak torque was assessed at 1.05, 3.14, and 5.23 rad · s−1 in concentric mode and at 3.14 and 5.23 rad · s−1 in eccentric mode. Concentric balance ratio and functional ratio were obtained. Bi-lateral deficiency was compared. Concentric strength for internal and external rotation was significantly greater for the dominant than for the non-dominant limb for all speeds (P ≤ 0.0001). For eccentric actions, internal rotator muscles were stronger in the dominant than the non-dominant limb (P ≤ 0.0001) at both speeds. Concentric balance and functional balance ratios did not differ between sides at 3.14 rad · s−1 (P = 0.1631), but at 5.23 rad · s−1 the functional balance ratio in the dominant limb was lower than for the non-dominant limb (P = 0.0500). Although the dominant side was stronger than the non-dominant side, balance concentric ratios remained the same, with only the functional strength ratio different at 5.23 rad · s−1. Our results suggest that concentric strength exercises be used for internal and external rotators on the non-dominant side, and functional exercise that improves eccentric rotation strength for prevention programmes.

Clinical Considerations for the Surgical Treatment of Pectoralis Major Muscle Ruptures Based on 60 Cases A Prospective Study and Literature Review

Background: Early recognition of the clinical signs of ruptures of the pectoralis major muscle (PMM) in athletes by orthopaedic surgeons, physical therapists, and physical trainers may prove to be critical for patient access to surgical treatment while the injury is still in the acute phase. Hypothesis: Total ruptures of the PMM may yield a better outcome with surgical treatment than with nonoperative treatment in athletes. Study Design: Cohort study; Level of evidence, 2. Methods: A prospective study was performed on 60 patients with total ruptures of the PMM. The patients were followed from 1997 to 2012, with a physical examination every 6 months for the first 2 years and every 12 months thereafter. The patients’ mean age was 31.21 years, and the mean length of follow-up was 48.25 months. The surgical treatment methods included reinsertion of the tendon in 51% of the patients and nonoperative treatment in 49% of the patients. All of the patients were evaluated using the Bak criteria. Results: The bench-press exercise was associated with 80% of the PMM ruptures (48 patients). Forty-one of the patients with chronic ruptures were seen after 3 months (80%). The outcomes were poor in 9 patients from the nonoperative group (31%) and in 3 patients from the surgical group (9.7%); the outcomes were fair in 12 patients from the nonoperative group and in no patients from the surgical group. Excellent results were not observed in any patient from the nonoperative group and were observed in 21 patients from the surgical group (67.7%). The isokinetic evaluation at 60 deg/s showed a decrease in strength of 41.7% in the nonsurgical group and 14.3% for the surgical group, which was significant at P < .05. Conclusion: Total ruptures of the PMM exhibit better outcomes with surgical treatment than with nonoperative treatment based on the Bak criteria in athletes.

Association between leisure time, physical activity, and mood disorder levels in individuals with epilepsy

The aim of this study was to investigate the association between physical activity levels (occupational, sports, and leisure time activities), depression, anxiety, and epilepsy. The behavioral outcomes of individuals with epilepsy (E) were also compared with healthy control subjects (C). The sample included 31 individuals with epilepsy (12 with idiopathic generalized epilepsy and 19 with partial epilepsy) and 31 control subjects. Self-rating questionnaires were used to assess mood (State-Trait Anxiety Inventory and Beck Depression Inventory), anxiety, and depression as well as habitual physical activity. Patients with epilepsy were more severely impaired compared to control subjects in both mood questionnaires and presented higher levels of depression (35%), state anxiety (18%), and trait anxiety (12.6%) when compared to the C group. Although physical activity level did not differ significantly between groups, linear regression analyses showed that the physical activity leisure level predicted 31% of depression levels and 26% of anxiety levels in the E group. These data suggest that low levels of physical activity may be considered a risk factor for the development of depression and anxiety and can play an important role in the quality of life of individuals with epilepsy.

Isokinetic muscle assessment after treatment of pectoralis major muscle rupture using surgical or non-surgical procedures

INTRODUCTION: Rupture of the pectoralis major muscle appears to be increasing in athletes. However, the optimal treatment strategy has not yet been established. OBJECTIVES: To compare the isokinetic shoulder performance after surgical treatment to that after non-surgical treatment for pectoralis major muscle rupture. METHODS: We assessed 33 pectoralis major muscle ruptures (18 treated non-surgically and 15 treated surgically). Horizontal abduction and adduction as well as external and internal rotation at 60 and 120 degrees/s were tested in both upper limbs. Peak torque, total work, contralateral deficiency, and the peak torque agonist-to-antagonist ratio were measured. RESULTS: Contralateral muscular deficiency did not differ between the surgical and non-surgical treatment modalities. However, the surgical group presented twice the number of athletes with clinically acceptable contralateral deficiency (<20%) for internal rotators compared to the non-surgical group. The peak torque ratio between the external and internal rotator muscles revealed a similar deficit of the external rotation in both groups and on both sides (surgical, 61.60% and 57.80% and non-surgical, 62.06% and 54.06%, for the dominant and non-dominant sides, respectively). The peak torque ratio revealed that the horizontal adduction muscles on the injured side showed similar weakness in both groups (surgical, 86.27%; non-surgical, 98.61%). CONCLUSIONS: This study included the largest single series of athletes reported to date for this type of injury. A comparative analysis of muscular strength and balance showed no differences between the treatment modalities for pectoralis major muscle rupture. However, the number of significant clinical deficiencies was lower in the surgical group than in the non-surgical group, and both treatment modalities require greater attention to the rehabilitation process, especially for the recovery of muscle strength and balance.

Shoulder isokinetic profile of male handball players of the Brazilian National Team

Background Data obtained on an isokinetic dynamometer are useful to characterize muscle status and have been reported in muscle imbalance studies in different types of sport. However, few studies have assessed elite handball players to establish reference values. Objective The purpose of this study was to compare, for the dominant (D) and non-dominant (ND) side, the isokinetic profile of shoulder rotator muscle strength between male handball players (H) and asymptomatic non-athletes (NA). Method Isokinetic concentric and eccentric strength tests for D upper limbs were performed by the H group (n=20) and the NA group (n=12). Internal and external rotator muscle peak torque in concentric action was assessed at 60°/s and 300°/s and in eccentric action at 300°/s. We also calculated conventional balance (the ratio of external rotator peak torque to internal rotator peak torque in concentric action) and functional balance (the ratio of external rotator peak torque in eccentric action to internal rotator peak torque in concentric action). Results In the H group, dominant limbs were stronger in concentric action for external rotation at 60 and 300°/s. The conventional balance ratio for the D side was significantly lower at 60 and 300°/s for H compared to NA. The functional ratio for the D side was significantly lower at 300º/s for H compared to NA. Conclusions Compared to asymptomatic non-athletes, handball players presented significant muscular imbalance resulting from daily sports practice, a known risk factor for shoulder injuries.

Heart rate response during a simulated Olympic boxing match is predominantly above ventilatory threshold 2: a cross sectional study

The present study aimed to describe heart rate (HR) responses during a simulated Olympic boxing match and examine physiological parameters of boxing athletes. Ten highly trained Olympic boxing athletes (six men and four women) performed a maximal graded exercise test on a motorized treadmill to determine maximal oxygen uptake (52.2 mL · kg−1 · min−1 ± 7.2 mL · kg−1 · min−1) and ventilatory thresholds 1 and 2. Ventilatory thresholds 1 and 2 were used to classify the intensity of exercise based on respective HR during a boxing match. In addition, oxygen uptake (V̇O2) was estimated during the match based on the HR response and the HR-V̇O2 relationship obtained from a maximal graded exercise test for each participant. On a separate day, participants performed a boxing match lasting three rounds, 2 minutes each, with a 1-minute recovery period between each round, during which HR was measured. In this context, HR and V̇O2 were above ventilatory threshold 2 during 219.8 seconds ± 67.4 seconds. There was an increase in HR and V̇O2 as a function of round (round 3 < round 2 < round 1, P < 0.0001). These findings may direct individual training programs for boxing practitioners and other athletes.

Stretch-Induced Reductions in Throwing Performance Are Attenuated by Warm-up Before Exercise.

Abstract Mascarin, NC, Vancini, RL, Lira, CAB, and Andrade, MS. Stretch-induced reductions in throwing performance are attenuated by warm-up before exercise. J Strength Cond Res 29(5): 1393–1398, 2015—Recent investigations have suggested that static stretching (SS) performed before exercise reduces muscular performance. However, it is yet unknown whether dynamic warm-up exercises performed together with SS may actually minimize the detrimental acute effects of stretching on muscular performance. This study aimed to assess the effects of static shoulder stretching exercises, dynamic warm-up exercises, or both together, on muscular performance evaluated by ball throwing. Twenty-one female handball players (age: 16.2 ± 1.0 years [range: 14–18 years], height: 167.0 ± 10.0 cm [range: 158–179 cm], and body mass: 63.3 ± 7.6 kg [range: 50.4–77.4 kg]) performed SS, dynamic warm-up exercises or both, targeting the muscles of the upper limbs. Thereafter, medicine ball throwing distance and handball ball throwing speed tests were performed. Static stretching performed before the medicine ball throwing test reduced performance when compared with the warm-up exercises (95% confidence interval [CI] = 0.02–0.17, p ⩽ 0.05, effect size [ES] = 0.34). When a warm-up exercise routine was added to SS, the detrimental effects of SS were abolished (95% CI = −0.01 to 0.18, p > 0.05, ES = 0.31). The throwing speed was the same over the 3 conditions. In conclusion, warm-up exercises performed together with SS abolished the impairment in medicine ball throwing distance. We recommend that athletes perform warm-up exercises together with SS before activity to avoid detrimental effects on muscle strength.