{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,29]],"date-time":"2026-09-29T16:03:16Z","timestamp":1790697796698,"version":"4.1.0"},"reference-count":30,"publisher":"Human Kinetics","issue":"10","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,10,1]]},"abstract":"\n \n Purpose<\/jats:italic>\n <\/jats:bold>\n :<\/jats:italic>\n To compare effects of block periodization against evenly distributed low-intensity training on endurance performance in well-trained junior cross-country (XC) skiers.\n \n Methods<\/jats:italic>\n <\/jats:bold>\n :<\/jats:italic>\n Twenty junior cross-country skiers participated in a crossover design study. Athletes were matched by maximal oxygen uptake (VO\n 2<\/jats:sub>\n max) and sex and were randomly assigned to either BLOCK or EVEN interventions, each lasting 4 weeks, separated by a 1-week break. BLOCK performed 1 week at 160% of baseline endurance volume, followed by weeks of reduced volume, while EVEN maintained consistent volume. Total training volume was identical between conditions. Pretesting and posttesting measured VO\n 2<\/jats:sub>\n max, maximal aerobic speed (\n V<\/jats:italic>\n max<\/jats:sub>\n ), and submaximal performance indices. Subjective markers of stress and recovery were also assessed daily.\n \n Results<\/jats:italic>\n <\/jats:bold>\n :<\/jats:italic>\n No significant treatment\u2013time interaction effects were found between the BLOCK and EVEN interventions for any performance variable, including VO\n 2<\/jats:sub>\n max (\n P<\/jats:italic>\n \u2009=\u2009.83,\n d<\/jats:italic>\n \u2009=\u2009\u22120.1),\n V<\/jats:italic>\n max<\/jats:sub>\n (\n P<\/jats:italic>\n \u2009=\u2009.15,\n d<\/jats:italic>\n \u2009=\u2009\u22120.4), or submaximal speed at 3\u00a0mmol\u22c5L\n \u22121<\/jats:sup>\n blood lactate concentration (V\n 3mmol\/L<\/jats:sub>\n ) (\n P<\/jats:italic>\n \u2009=\u2009.55,\n d<\/jats:italic>\n \u2009=\u20090.2). While both groups demonstrated significant within-group improvements in some performance variables, these gains were not statistically different between the 2 periodization strategies. The BLOCK group, however, reported significantly lower mood and perceived recovery during the high-volume week and the subsequent recovery week.\n \n Conclusion<\/jats:italic>\n <\/jats:bold>\n :<\/jats:italic>\n Block periodization of low-intensity training is not more effective for improving endurance performance in junior cross-country skiers than volume-matched, evenly distributed training. The concentrated, high-volume week of low-intensity training was well-tolerated and safe but failed to provide an additional performance stimulus. The findings indicate that for training with a lower physiological stress profile, consistent application, rather than concentration, is the primary driver of adaptation.\n <\/jats:p>","DOI":"10.1123\/ijspp.2025-0552","type":"journal-article","created":{"date-parts":[[2026,5,23]],"date-time":"2026-05-23T16:04:39Z","timestamp":1779552279000},"page":"1164-1171","source":"Crossref","is-referenced-by-count":0,"title":["No Additional Effects of Block- Compared to Even-Periodization of Low-Intensity Training in Junior Cross-Country Skiers"],"prefix":"10.1123","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0009-0001-4108-7566","authenticated-orcid":true,"given":"Jacob","family":"Walther","sequence":"first","affiliation":[{"name":"School of Medicine and Health, Experimental Exercise Science, Technical University Munich, M\u00fcnchen, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lars","family":"H\u00e4nel","sequence":"additional","affiliation":[{"name":"German Ski Federation, Planegg, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ronja","family":"Krohn","sequence":"additional","affiliation":[{"name":"Olympic Training Centre Saxony, Chemnitz, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Steffen","family":"Gro\u00dfmann","sequence":"additional","affiliation":[{"name":"Olympic Training Centre Saxony, Chemnitz, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9605-3489","authenticated-orcid":true,"given":"Moritz","family":"Schumann","sequence":"additional","affiliation":[{"name":"School of Medicine and Health, Experimental Exercise Science, Technical University Munich, M\u00fcnchen, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"100","reference":[{"issue":"1","key":"r1","series-title":"J Physiology","doi-asserted-by":"publisher","first-page":"35","DOI":"10.1113\/jphysiol.2007.143834","article-title":"Endurance exercise performance: the physiology of champions","volume":"586","author":"Joyner MJ","year":"2008","unstructured":"Joyner MJ, Coyle EF. 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