Summary of findings for muscle activity studies (n=9)
| Study | Findings | Narrative |
| Gill et al 201237 | US measures of trunk muscle thickness found a difference in absolute thickness of TRA between oarside and non-oarside (4.47±0.78 mm vs 4.70±0.94 mm, p=0.038). No difference in absolute thickness of the IO (10.69±2.13 mm vs 11.06±2.47 mm, p=0.135), EO (10.37±1.98 mm vs 10.22±2.25 mm, p=0.503) or the total abdominal thickness from side to side (25.60±3.83 mm vs 26.01±4.16 mm, p=0.291). Significant difference in relative thickness of the EO between oarside and non-oarside (41.5%±4.7% vs 40.2%±5.0%, p=0.05). | No relationship to LBP or hand dominance measured. Findings unlikely to be clinically meaningful or have relevance to LBP in rowers. |
| Klein et al 199140 | Comparison of ROM in standing, sitting and MVC of same muscle groups during rowing to investigate if screening out of boat is relevant; 63% of healthy rowers were correctly identified; 57% of rowers with LBP were correctly identified. | The commonly used evaluative techniques of ROM and muscle strength testing cannot distinguish LBP from not. Hard to see relevance of this study. |
| Martinez-Valdes et al 201912 | As work intensity ↑, rowers with LBP showed significantly higher amplitude (*no mean±SD data provided, p<0.01) and less complexity (entropy) of the HDEMG signals (*no mean±SD data provided, p<0.001). Rowers with LBP showed opposite displacements of the barycentre, with the LBP group showing a caudal shift of muscle activity at high intensities (*no mean±SD data provided, p<0.001). | Rowers with history of LBP do not recruit ES efficiently when fatiguing, shifting recruitment caudally (reducing) as opposed to extending recruitment through larger portions of muscle as seen in the healthy (no LBP) group. Very little trunk flexor activity in rowers’ trunks. Only used at end of drive phase in shift from drive to recovery. |
| McGregor et al 2002b41 | Cross-sectional area of the ES, MF and IP was significantly greater in those with current LBP (left ES: 889.4±105.8 mm2, right ES: 915.4±181.9 mm2; left MF: 352.4±108.8 mm2, right MF: 371.0±104.1 mm2; left IP: 1347.8±457.2 mm2, right IP: 1348.8±399.0 mm2) or a history of LBP (left ES: 931.6±399.1 mm2, right ES: 889.2±459.3 mm2; left MF: 422.2±196.6 mm2, right MF: 426.3±186.3 mm2; left IP: 1343.9±345.9 mm2, right IP: 1398±407 mm2) compared with healthy rowers (left ES: 745.0±213.9 mm2, right ES: 751.3±205.0 mm2; left MF: 226.3±35.0 mm2, right MF: 235.5±48.7 mm2; left IP: 993.3±254.8 mm2, right IP: 916.3±207.0 mm2). | Considerable differences were observed between the three groups of rowers. Trunk muscles of rowers with LBP had significantly larger cross-sectional areas. No left/right asymmetries were observed and no differences between oarside and non-oarside in terms of muscle cross-sectional area. |
| McGregor et al 2004a42 | The rowers were significantly stronger (p<0.001) in all measured parameters of trunk strength than the CONT group (isometric extension strength 249.3±52.1 N/m in rowers compared with 178.6±85 N/m in CONT). Greater strength in the rowing group was most significant in the later stages of range (p<0.01). Both populations demonstrated marked fatigue of the trunk muscles, although this was more prominent in the rowers during trunk flexor testing (flexion fatigue scores 84.0%±24.7% for rowers and 95.4%±21.8% for CONT, p<0.05). | Values of trunk extensor strength were greater than trunk flexor strength, although this was less so in rowers. The trunk extensor-flexor ratios were lower in rowers. Rowers showed greater levels of fatigue than CONT during testing of the trunk flexors. Elite rowers are significantly stronger than CONT. |
| Nowicky et al 200536 | No significant differences in sEMG activity of the RF (0.081±0.019 mV·s vs 0.060±0.015 mV·s, p=0.06), BF (0.075±0.030 mV·s vs 0.072±0.014 mV·s, p=0.81), ES (0.067±0.032 mV·s vs 0.048±0.019 mV·s, p=0.25) and RA (0.047±0.019 mV·s vs 0.042±0.022 mV·s, p=0.64) between the Concept 2 and Rowperfect ergometer, respectively. No significant differences in hip ROM (101.6°±4.5° vs 99.5°±2.7°, p=0.35) or knee ROM (118.3°±5.0° vs 115.8°±6.7°, p=0.53) between the Concept 2 and Rowperfect ergometer, respectively. | No differences in muscle activity or knee and hip ROM when dynamic and fixed ergometers were compared. |
| Parkin et al 200114 | Rowers were stronger than CONT in the knee extensors (*no mean±SD data provided, p<0.01) but not in the knee flexors (*no mean±SD data provided) or trunk extensors/flexors (*no mean±SD data provided). No side-to-side differences in either group regarding any of the leg strength measurements. Rowers had significantly greater EMG signals than CONT in trunk extension and flexion (p<0.001) and a trend towards asymmetric EMG recordings according to side rowed was noted for the rowers (p=0.07). | It is speculated that the lack of increased trunk muscle strength of the rowers compared with CONT could be a risk factor for LBP in the rowers. |
| Pollock et al 200939 | The pelvic and the spinal extensor muscles demonstrated similar timing of activation during the stroke (time of peak amplitude in BF at 18.3%±2.4%, GM at 17.1%±4.7%, ES lumbar at 18.5%±3.5% and ES thoracic at 18.5%±4.8%), as did the flexor muscles (time of peak amplitude in TRA/IO at 41.3%±3.1%, RA at 40.4%±2.4% and EO 40.5%±2.6%). During the period of PF production, there was minimal coactivation of the flexors and the extensors.The motion of the spine was minimal during PF production, although there was significantly more extension at L3–S1 than at any other segment (2.9°±1.0°, p=0.0001). Low levels of coactivation of the trunk flexors and extensors existed in late drive during the transition between predominately extension to predominately flexion activity. | Detailed description of pelvic/spinal movement pattern and timing of trunk muscle (+BF) activation during the rowing stroke in healthy elite rowers. Not a particular focus on LBP. |
| Roy et al 199043 | A two-group discriminant analysis procedure correctly classified 100% of rowers with LBP and 93% of rowers without LBP based on median frequency data. | Rowers with LBP can be identified by EMG characteristics. Not clear from paper what these are and authors were not blinded to LBP status. |
LBP; low back pain, ROM; range of motion, MVC; maximal voluntary contraction, US; ultrasound, HDEMG; high-density electromyography, EMG; electromyography, sEMG; differential surface electromyographic, TRA; transversus abdominis, IO; internal oblique, EO; external oblique, ES; erector spinae, MF; multifidus, ILP; iliopsoas, BF; bicep femoris, RF; rectus femoris, RA; rectus abdominis, GM; gluteus maximus, PF; peak force, CONT; control.
BF, bicep femoris; CONT, control; EMG, electromyography; EO, external oblique; ES, erector spinae; GM, gluteus maximus; HDEMG, high-density electromyography; ILP, iliopsoas; IO, internal oblique; LBP, low back pain; MF, multifidus; MVC, maximal voluntary contraction; PF, peak force; RA, rectus abdominis; RF, rectus femoris; ROM, range of motion; sEMG, differential surface electromyographic; TRA, transversus abdominis; US, ultrasound.