TY - JOUR A1 - Müller, Steffen A1 - Stoll, Josefine A1 - Mueller, Juliane A1 - Cassel, Michael A1 - Mayer, Frank T1 - Trunk Muscle Activity during Drop Jump Performance in Adolescent Athletes with Back Pain JF - Frontiers in physiology N2 - In the context of back pain, great emphasis has been placed on the importance of trunk stability, especially in situations requiring compensation of repetitive, intense loading induced during high-performance activities, e.g., jumping or landing. This study aims to evaluate trunk muscle activity during drop jump in adolescent athletes with back pain (BP) compared to athletes without back pain (NBP). Eleven adolescent athletes suffering back pain (BP: m/f: n = 4/7; 15.9 +/- 1.3 y; 176 +/- 11 cm; 68 +/- 11 kg; 12.4 +/- 10.5 h/we training) and 11 matched athletes without back pain (NBP: m/f: n = 4/7; 15.5 +/- 1.3 y; 174 +/- 7 cm; 67 +/- 8 kg; 14.9 +/- 9.5 h/we training) were evaluated. Subjects conducted 3 drop jumps onto a force plate (ground reaction force). Bilateral 12-lead SEMG (surface Electromyography) was applied to assess trunk muscle activity. Ground contact time [ms], maximum vertical jump force [N], jump time [ms] and the jump performance index [m/s] were calculated for drop jumps. SEMG amplitudes (RMS: root mean square [%]) for all 12 single muscles were normalized toMIVC (maximum isometric voluntary contraction) and analyzed in 4 time windows (100 ms pre- and 200 ms post-initial ground contact, 100 ms pre- and 200 ms post-landing) as outcome variables. In addition, muscles were grouped and analyzed in ventral and dorsal muscles, as well as straight and transverse trunk muscles. Drop jump ground reaction force variables did not differ between NBP and BP (p > 0.05). Mm obliquus externus and internus abdominis presented higher SEMG amplitudes (1.3-1.9-fold) for BP (p < 0.05). Mm rectus abdominis, erector spinae thoracic/lumbar and latissimus dorsi did not differ (p > 0.05). The muscle group analysis over the whole jumping cycle showed statistically significantly higher SEMG amplitudes for BP in the ventral (p = 0.031) and transverse muscles (p = 0.020) compared to NBP. Higher activity of transverse, but not straight, trunk muscles might indicate a specific compensation strategy to support trunk stability in athletes with back pain during drop jumps. Therefore, exercises favoring the transverse trunk muscles could be recommended for back pain treatment. KW - SEMG-pattern KW - back pain KW - pre-activity KW - drop jump KW - neuromuscular KW - trunk KW - performance KW - young athletes Y1 - 2017 U6 - https://doi.org/10.3389/fphys.2017.00274 SN - 1664-042X VL - 8 SP - 124 EP - 132 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Müller, Steffen A1 - Stoll, Josefine A1 - Cassel, Michael A1 - Mayer, Frank T1 - Trunk Muscle Activity during Drop Jump Performance in Adolescent Athletes with Back Pain JF - Frontiers in physiology N2 - In the context of back pain, great emphasis has been placed on the importance of trunk stability, especially in situations requiring compensation of repetitive, intense loading induced during high-performance activities, e.g., jumping or landing. This study aims to evaluate trunk muscle activity during drop jump in adolescent athletes with back pain (BP) compared to athletes without back pain (NBP). Eleven adolescent athletes suffering back pain (BP: m/f: n = 4/7; 15.9 ± 1.3 y; 176 ± 11 cm; 68 ± 11 kg; 12.4 ± 10.5 h/we training) and 11 matched athletes without back pain (NBP: m/f: n = 4/7; 15.5 ± 1.3 y; 174 ± 7 cm; 67 ± 8 kg; 14.9 ± 9.5 h/we training) were evaluated. Subjects conducted 3 drop jumps onto a force plate (ground reaction force). Bilateral 12-lead SEMG (surface Electromyography) was applied to assess trunk muscle activity. Ground contact time [ms], maximum vertical jump force [N], jump time [ms] and the jump performance index [m/s] were calculated for drop jumps. SEMG amplitudes (RMS: root mean square [%]) for all 12 single muscles were normalized to MIVC (maximum isometric voluntary contraction) and analyzed in 4 time windows (100 ms pre- and 200 ms post-initial ground contact, 100 ms pre- and 200 ms post-landing) as outcome variables. In addition, muscles were grouped and analyzed in ventral and dorsal muscles, as well as straight and transverse trunk muscles. Drop jump ground reaction force variables did not differ between NBP and BP (p > 0.05). Mm obliquus externus and internus abdominis presented higher SEMG amplitudes (1.3–1.9-fold) for BP (p < 0.05). Mm rectus abdominis, erector spinae thoracic/lumbar and latissimus dorsi did not differ (p > 0.05). The muscle group analysis over the whole jumping cycle showed statistically significantly higher SEMG amplitudes for BP in the ventral (p = 0.031) and transverse muscles (p = 0.020) compared to NBP. Higher activity of transverse, but not straight, trunk muscles might indicate a specific compensation strategy to support trunk stability in athletes with back pain during drop jumps. Therefore, exercises favoring the transverse trunk muscles could be recommended for back pain treatment. KW - SEMG-pattern KW - back pain KW - pre-activity KW - drop jump KW - neuromuscular KW - trunk KW - performance KW - young athletes Y1 - 2017 U6 - https://doi.org/10.3389/fphys.2017.00274 SN - 1664-042X VL - 8 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Musalek, Martin A1 - Kokstejn, Jakub A1 - Papez, Pavel A1 - Scheffler, Christiane A1 - Mumm, Rebekka A1 - Czernitzki, Anna-Franziska A1 - Koziel, Slawomir T1 - Impact of normal weight obesity on fundamental motor skills in pre-school children aged 3 to 6 years JF - Journal of biological and clinical anthropology : Anthropologischer Anzeiger ; Mitteilungsorgan der Gesellschaft für Anthropologie N2 - Normal weight obesity is defined as having excessive body fat, but normal BMI. Even though previous research revealed that excessive body fat in children inhibited their physical activity and decreased motor performance, there has been only little evidence about motor performance of normal weight obese children. This study aims to establish whether normal weight obese pre-school children aged 3-6 years will have a significantly worse level of fundamental motor skills compared to normal weight non-obese counterparts. The research sample consisted of 152 pre-schoolers selected from a specific district of Prague, the Czech Republic. According to values from four skinfolds: triceps, subscapula, suprailiaca, calf, and BMI three categories of children aged 3-6 years were determined: A) normal weight obese n = 51; B) normal weight non-obese n = 52; C) overweight and obese n = 49. The Movement Assessment Battery for Children (MABC-2) was used for the assessment of fundamental motor skills. Normal weight obese children had significantly higher amount of adipose tissue p < 0.001 than normal weight non-obese children but the same average BMI. Moreover, normal weight obese children did not have significantly less amount of subcutaneous fat on triceps and calf compared to their overweight and obese peers. In majority of MABC-2 tests, normal weight obese pre-schoolers showed the poorest performance. Moreover, normal weight obese children had significantly worse total standard score = 38.82 compared to normal weight non-obese peers = 52.27; p < 0.05. In addition, normal weight obese children had a more than three times higher frequency OR = 3.69 CI95% (1.10; 12.35) of severe motor deficit performance <= 5th centile of the MABC-2 norm. These findings are strongly alarming since indices like BMI are not able to identify normal weight obese individual. We recommend verifying real portion of normal weight obese children as they are probably in higher risk of health and motor problems than overweight and obese population due to their low lean mass. KW - normal weight obesity KW - fundamental motor skills KW - MABC-2 KW - performance KW - pre-school children KW - skinfolds KW - adipose tissue KW - lean mass Y1 - 2017 U6 - https://doi.org/10.1127/anthranz/2017/0752 SN - 0003-5548 VL - 74 SP - 203 EP - 212 PB - Schweizerbart CY - Stuttgart ER - TY - JOUR A1 - Lampart, Fabian T1 - Form and Content, Again BT - four remarks on lyric theory JF - Journal of Literary Theory N2 - The following statement suggests reconsidering recent debates on a theory of lyric in terms of form and content. Four aspects and issues of the ongoing debate are discussed. In a first step, it is necessary to establish the relation between authorial poetics and lyric theory, since it is often characterised by fuzzy boundaries. Secondly, in order to specify the problem of form in lyric theory, it is suggested to have a closer look at the performative in lyric practice. Another important aspect of form is the semantics of lyrical genres. Lyrical genres mark an area in which form and content are intertwined and in which aspects of the form itself become semantic. Finally, the author argues that we should discuss - if possible assisted by a didactics sensitive to literary texts - whether and how theoretical proposals could be transformed into a practice of teaching poetry. KW - lyric KW - form KW - content KW - poetry and poetics KW - performance KW - teaching poetry Y1 - 2017 U6 - https://doi.org/10.1515/jlt-2017-0008 SN - 1862-5290 SN - 1862-8990 VL - 11 IS - 1 SP - 74 EP - 82 PB - De Gruyter CY - Berlin ER -