Rashi: It is lamenting, like "u'Mi Yanud Lach" (15:5).

Radak: It is crying and groaning.

Malbim: He laments and disputes with Hashem.

Radak: You afflicted me for many years in exile, and I was chastised.

Malbim: There are two ways to return the nation in Teshuvah. (a) Via afflictions - then they repent amidst fear. (b) If Hashem reveals His Elokus via miracles and wonders, until all recognize His Hashgachah, and they repent amidst love. Hashem wanted to return Efrayim via afflictions; Efrayim laments that this did not help - I was afflicted, but I did not return.

Rashi: It was not trained to bear a yoke. Lumad is like "Malmed ha'Bakar" (Shoftim 3:31). So I was initially, therefore I sinned against You.

Radak: They did not train it to pull a yoke. It does not learn until they hit it and train it. So I suffered afflictions and learned to return to You - behold, I return to You!

Sha'arei Teshuvah (1:11): A calf is not trained [to plow straight]; one hits it to return it to the path. So one who is on a bad bath, first he must take Musar to abandon the way of death to go in the straight path.

Malbim: An ox trained to plow, when it veers from the furrow and one hits it, it returns to the furrow. A calf, which is not trained, when one hits it, it makes its path even more crooked. So via afflictions, I strayed even more!

Radak: Accept my Teshuvah.

Malbim: Help me to repent via showing to me Your special Hashgachah and Elokus, until I return in Teshuvah amidst love and knowledge of Elokim.